Ok here it goes... It will be a very long text (...as if you would expect anything else from me ... ) 
. I assembled a lot of texts I wrote in the past and linked them all together to make this tiny novel...
Introduction:My text is very long but I think I covered most of what had to be covered. Remember that the community is now 13 years old and it encompasses many different persons from whom ideas or creations emerged and merged to get URU to the present state which has hardly anything to do with the original URU as Cyan intended. It’s hard to get a full picture of what URU is because in 2014, there’s even no more original URU in any form…
Theoretically,
there are 2 “official” URU games:
URU:CC (offline) &
MOUL (online). They both have been released under compromise over the last 13 years. URU:CC was released 2 years after the first version of URU Live went down in early 2004
(Correction made here). Cyan released that offline version (URU:CC) which bundled every available ages at that moment. In 2007, Cyan associated themselves with Gametap to release a new online version of their game under a new name: MOUL. The physics engine used before (HavoK) wasn’t the one they used for MOUL. They used instead an another physics engine (physX) which leads to disastrous results
(Correction made here). The game was suited for HavoK not really for physX resulting in a lot of bugs, broken animations among the most popular like the Zandoni ride, the Maintainer’s Wall, & the Great Tree Pub.
In other words, the original URU cannot be found in either URU:CC or MOUL.
None of the URU versions out there can give you everything. On the good hand, this community is populated by many devoted coders, programmers, creators, etc that over time fixed, built, imagined, created what we have today. The community decided to work on the flaws to a point that we see today: great online servers with little bugs giving each a version of URU that slightly differs from one to another.
There are many servers out there, Deep Island, TOC MOUL, & Gehn are 3 great examples of URU game servers. In this community we call them shards. I will refer to them as DI, TOC MOUL, & Gehn. It’s very interesting that you come up with these 3 shards because they are running each on a different type of server...
Different type of server means different possibilities, different issues, different bugs, but also different gaming experiences. It’s therefore very hard to compare them as they are very different. The only similarity they all have in common is the game itself: URU with the reserve I already explained earlier and what is coming.
Presentation of each shard:GehnGehn is developed on a constant basis by a team of coders all members of the Guild of Writers. It’s the official shard of the Guild. Gehn is a very well coded game and everything looks sharp. The developers are looking for the very little details and make small fixes to ensure we get the best gaming experience. Visually, the game on Gehn is astonishing. The 4 fan-made ages on Gehn are well-integrated in the URU Storyline, it’s less obvious with Trebidvil but the age is a nice contemplative zen-like garden planted in the middle of an endless sea. It is not a silly age.
On the other hand, Gehn is running on a unique type of server called Dirtsand developed by the GoW’s coders themselves. That server is very stable but some elements of the game play are totally inoperative, for example the marker quests don’t work on that shard. We cannot complete the GZCM process either because the last steps involve playing marker quests (the 14 GZCM quests). Gehn shard is still in development and the bugs generally get fixed on a timely basis making the gaming experience a great one.
Gehn was developed right after the announcement by Cyan that they released their game code to open-source in early July 2012. Gehn is therefore running game content that originates from Cyan’s files, it’s a MOUL-based shard. We can openly discuss of that shard over MOULa forum although the GoW’s forum is more appropriate, it’s their baby.
TOC MOULTOC MOUL is also a MOUL-based shard. The shard was also developed in summer 2012 (August if I recall it right) after the release of the game code by Cyan to open-source. The shard runs on a server type that differs from Gehn, it’s called MOSS. It's a fan-made server developed
(Correction made here). There are many shards running on a MOSS server. All of them are approved by Cyan. The Open-Cave team has its own forum. It would be always preferable to discuss on that forum about their shards (they have more than one...) instead of here but the actual discussion is about comparing 3 specific shards of which 2 are linked to this forum (DI & Gehn) and the TOC team members are also active members of this forum.
TOC MOUL has a special development. It’s a 2 ways development scheme. On one side, the developers fix bugs, develop contents, & maintain their server and on the other side, they import bug fixes and new fan-made ages integrated in Gehn. Usually, an update on Gehn is followed by a similar one on TOC MOUL in the following weeks. Some would be tempted to say they are only copycat but let’s go a little deeper to see if that’s the truth.
TOC team has reactivated the long lost Maintainer Training Wall that was lost since Until URU. The marker quests are fully functional on their shard. You can complete the GZCM process. They created a copy of D’ni-Ae’gura that they call “The City of Dimension” (more commonly known as COD among explorers). In that age, most of the void planes of Ae’gura have been made solid therefore they are reachable and this lead to an exploration feast. You can go everywhere: the highest balcony of the Palace, reachable, the highest stalagmite summit, reachable, standing beside the Arch, possible. The original city of Ae’gura is still reachable and is left intact. TOC team also enabled some KI functions that are not possible on Gehn. You can have a complete listing by typing “/help” when you are online.
Because of the possibility to use cheat commands like “/jump” or silly commands like swimming in thin air, you can see explorers in some ages making use of them; I’ll say it breaks the immersion of playing URU in a canon way. You won’t see those behaviours on Gehn for instance because, there is no equivalent; the KI functions are the same as the ones available on MOULa (the official shard run by Cyan).
Deep IslandDI is a shard that runs on a type of server that was developed a long time ago long before the release of the game code to open-source. The server is called an alcugs server. There are 3 running alcugs shards of which DI is the most popular one. The server code comes from a hack of the offline game (URU:CC). This is the reason why I strongly suggested you, Chapel, to move your discussion to the GoW forum instead of using the MOULa forum. One of their forum rules is that we cannot openly talk about program or way to hack any of Cyan’s products, URU:CC is one of them. So why, this type of server is still popular and running although the server code is no longer developed and it’s openly a hack of copyrighted works? An alcugs server gives the vastest gaming experience of URU ever of all the servers available out there. I don’t use the adjective “complete” but “vast”. As I said before, there’s no “complete” experience available.
BTW, it’s all legal issue here, I mean, behind closed doors, no one in Cyan cares about DI running alongside more legit shards. They just don’t openly give their consent because of third parties (with long sharp teeth...)To play on DI, you first need to have a legit copy of URU:CC. (You can also have a legit copy of URU:ABM and add the expansion packs “To D’ni” (free) and “TPoTS” (that you paid for)). The game server will modify (that’s a more gentle word than hack LOL) your game files to transform your offline game to an online game. The conversion from the offline game to an online game will definitely break some inner workings especially in Ahnonay. You have to understand the real issue here though. Ahnonay was meant to be a multi-player age. URU:CC has a badly modified code version to make it work as a standalone single player age. It was impossible to reverse engineer that new code to make it work back as a multi-player age.
There also another thing that you have to understand, as I said before in the text, the alcugs server code was developed a long time ago. It was developed during a dark era of URU history in-between MOUL (Gametap era 2007-2008) and MOULa (2010-2012). The game code of the online game was unavailable so the only unique solution to all this was to develop an online game from the only unique source available at that time: the offline game (URU:CC). Taking that into consideration, you get one hell of a server that runs quite smoothly and has few bugs. Officially, there is no more development on the server code itself. The bugs that were present 2 years ago are therefore always present and will still be in the future. There are still some aficionados of URU:CC (among them we can count Sirius, a French coder). He modified the code of the maintainer’s wall so that it works. The DI admin, Diafero, made some modifications to his shard so that the code developed by Sirius made its way to the shard. So the core server code is in an arrested development but some fixes can always be added from time to time.
I always promote the fact that this shard holds approximately 130 fan-made ages. It’s a huge number and obviously the quality of those ages goes from Naïve Art to Masterpiece. One thing that is great though, is the choice given to the explorers themselves. Take a sample of 20 explorers and you won’t have the same DI install on all their computers.
Let me explain. Let’s say an explorer wants the core ages and likes very much the canon ages, the pure D’ni ages. If we inspect their DI install, we won’t be surprised to see they have the core ages plus some ages like Vothol Gallery, Tsoidahl Prad, Fehnir’s House, Kaelis’ Pub Office, & ages alike. Let’s take another explorer. That guy likes very much complex ages with lots of areas to explore. We wouldn’t be surprised to see they have installed Elodea, Somewhere, Iceworld, Calena’s ages (Rahsoo & R’Osha), & other ages alike. The bottom line is that you can choose what you want to add to your basic DI install. When the server is converting your offline game into an online game, it imports contents from MOULa that’s it that’s all. All the remaining is customisable.
Theoretically, you can add up to 150 ages to your URU core ages using DI, to have the vastest experience ever. For that you need to visit all of the 130 fan-made ages & possess legit copies of Myst 5 EOA game, of Crowthistle CD, of Cosmic Cosmo’s HexIsles game, & of the now former MagiQuest Online game’s files (that you paid for).
No visit, no harm !
The way to install a fan-made age on your DI install is to visit the age. As long as you stay away of any unwanted fan-made age, meaning that you don’t set foot there in game, you won’t have them installed on your PC. So this is a false issue that DI contains many silly non-canon ages. But yes you can set foot in some awkward ages if you want.
Game Play Detailed Explanations: SPOILERS ALERTFor the core ages themselves, DI differs greatly from the other shards. Remember that most of the servers run under the open-source game code making them de facto MOUL-based shard. The core ages runs just like their MOULa shard equivalent.
In DI, we start from another game base: URU:CC and the server imports some elements from MOULa game files and mix them together to make a sort of hybrid game that has nothing to do with MOULa nor with URU:CC offline.
Game play in URU:CCIn URU:CC, you start in the Cleft clueless. You have to complete the puzzle there to have access to your Relto. Once in your Relto, you have the choice of playing what we call the Yeesha Journey (Kadish, Gahreesen, Teledahn, & the Eders), exploring D’ni (Bevin, Phil’s Relto (need Teledahn though), Kirel, the Great Zero, & D’ni-Ae’gura), or playing the TPoTS Journey (Ahnonay, Er’cana, The Watcher’s Pub, D’ni-K’veer, & Myst Library). The Yeesha Journey is pretty much simple: touching the clothes spread everywhere, visit the bahro caves bring the totems to your Relto then bring them back to the Bahros and visit back the Cleft for the final sequence. Exploring D’ni will help you collect all the markers needed to calibrate the Great Zero (4 green – 15 red – 4 yellow), those markers are called the GZCM (The Great Zero Calibration Markers). The end result is the activation of the GZ laser beam and an access to URU:CC’s D’ni-Tiwah (the great shaft). The TPoTS Journey is the most difficult one. You need to gather all the notes scattered everywhere inside 3 ages to find a hidden message. You then have to follow its instructions to follow the path of the shell to link to D’ni-K’veer and to then be transported to the final sequence. The solving involves making pellets and waiting times. You also need to gather scattered pieces of a whole diagram to unlock the Myst Library’s fireplace.
Game play in MOUL This is pertaining to both Gehn and TOC MOUL shardsIn MOUL, you begin directly in your Relto. The Yeesha Journey goes the same way as in URU:CC. The difference here is that you have to manually go to the Cleft to start it. The GCZM process can be done at any time. Since it’s an online game, it would have been hardly believable to explorers to calibrate the GZ itself when knowing a lot of explorers must have calibrated it already in the past. Cyan decided to change the whole process. Your KI can now be some sort of GPS device when you are standing in D’ni Cavern ages (mainly the city & the neighbourhoods). In order to unlock this option, you need to complete all the GZCM process which consists of 3 steps (15 green – 15 red – 228 yellow inside 14 marker quests). If you just want to play marker quests made by other explorers or make some yourself, you just need to complete the first 2 steps (15 green – 15 red). The TPoTS Journey is completely different in MOUL. The Watcher’s Pub is replaced by an alternate pub called The Great Tree Pub (although in-game the name is “The Watcher’s Pub”, don’t be fooled though, the age is different from the genuine Watcher’s Pub). URU:CC’s D’ni-K’veer has been replaced by Myst 5 EOA’s D’ni-K’veer.
All the puzzle logic of URU:CC’s for the TPoTS Journey has been abandoned to an alternative puzzle. All you need in MOUL is to find a way to enlighten a two storey bahro cave to see a diagram on a wall on the lower cave. It seems simplistic but you need to find a way to reach that lower level, a way to reach the upper level, to make pellet to get some light, & to find the way to be simultaneously present on the lower level to see the diagram and on the upper level to drop the pellet. Needless to say, all the solving of TPoTS requires a second explorer... Even the solving of Ahnonay cannot be done alone. Once you get the diagram, you need to go back in the Cleft, enter it into the imager & link to D’ni-K’veer and the Myst Library.
There are 3 more journeys in MOUL: the Scar Journey, the Spiral Journey, & the Pod Journey. The Scar Journey takes place inside Minkata, an astonishingly hard journey but one of the greatest one. The Spiral Journey takes place inside 2 nice gardens: Eder Delin & Eder Tsogal. That journey has to be performed in multi-player mode. It’s a great way to develop connection between you and other explorers; you need to be a party of 8 to make the journey smooth. The Pod Journey is so hard to solve that most explorers relies on Websites telling the time of the next upcoming portals to finish it. You’ll visit nice enclosed areas where you will be able to see exterior wildlife, apart the sombre & uninviting Tetsonot where your discomfort & fear levels will be highly tested.
Game play on DIOn DI, you will be playing a hybrid game between the 2 above. Even the Yeesha Journey is a hybrid one. You’ll start the game clueless in the Cleft just like URU:CC. Upon reaching your Relto, you’ll be able to play any of the Journeys available on MOUL. The Relto pages that you’ll gather throughout the Yeesha Journey are those of MOUL not only the ones found in URU:CC adding more stuff to your Relto. You’ll gather bahro wedges for each step of your numerous journeys. The GCZM process follows the process of URU:CC (4 green – 15 red – 4 yellow) even though the GZ should be functional since many explorers have already calibrate it in the past. You can make marker quests after the green & red markers gathering. Those markers are not the same as the ones in MOUL. I call them the yellow ones. They are more subject to bugs & you cannot stand in any. As soon as you get in the vicinity of one, you’ll grab it. Grabbing one will produce some lag, enough to make a landing on a yellow marker spot unstable. In MOUL, the markers available to explorers are purple. They are less subject to bugs, you can reset a quest to stand exactly on the marker spot; you’ll see your avatar standing inside it. The landing on such marker creates little to no lag.
The TPoTS journey has to be solved like in URU:CC. Ahnonay puzzle logic is somewhat broken (already discussed previously) so the crabs are disabled as well as the ning trees. Since Ahnonay is a multi-player age but must be solved alone, the solving can be awkward as one explorer exploring Ahnonay can interfere with the solving of that age by another explorer without knowing it. Every modification brought to Ahnonay by any explorer will affect everybody else. You don’t have an Ahnonay, you share it. To grab the 2 bahro wedges of MOUL’s TPoTS Journey, the server has modified your Er’cana to let you go through the portal in your canyon right from the start. For Ahnonay, it’s a little bit trickier. To go around the issue of adding a balcony to reach the portal in Kadish Office in the middle of the Vortex in Ahnonay, there are 2 versions of Ahnonay on DI, URU:CC’s (the main one) and a modified MOUL’s that only gives you instant access to the Kadish Office balcony to reach the bahro cave to grab your bahro wedge. Each Ahnonay is therefore available in their own “Watcher’s Pub”. The MOUL’s version is called “The Great Tree Pub” reachable through the Nexus links. The URU:CC’s version is called “The Watcher’s Sanctuary” and it’s reachable directly from your Relto’s upper bookshelf. In addition to all that, you also have 2 versions of D’ni-K’veer: the URU:CC’s and the MOUL’s. The URU:CC’s is reachable by solving the TPoTS Journey and the MOUL’s one is reachable by an added bahro stone hidden somewhere in Ae’gura
(the stone itself is not hidden from view, I just don’t want to disclose where it is).
You can play the Scar Journey just like you can do it in MOUL. The same applies with the Pod Journey. For the Spiral Journey, you need to do the same as you did in MOUL, gather a party of 8 and solve the 2 garden ages.
In addition to all that,
you’ll have access to the Zandoni ride (you’ll ultimately crash at the end of the ride, either by turning the Zandoni over or just because you cannot exit the engine even by Reltoing out of there, that’s a bug) and you can play on the Maintainer’s Wall. You’ll have access to 2 versions of D’ni-Kirel as well: the URU:CC’s called “The D’ni Neighbourhood” reachable by the Phil’s Relto and the MOUL’s called “The Guilds Neighbourhood” reachable by an added bahro stone in the city
(again, I won’t disclose its location, yours to find out). There’s also an added neighbourhood called “Seret”. The latter is created during the importation of MOULa’s game files. The authors of this age made sure to only enable canon elements of a default MOULa’s Neighbourhood to fit the conception of how the Seret Neighbourhood should look like. You have therefore access to 4 neighbourhoods on DI: yours, Seret, & 2 versions of Kirel.
If you add Myst 5 EOA to your DI install...
...which I highly recommend because it fits naturally the storyline itself, you’ll gain 8 ages namely Myst 5 EOA’s D’ni-Tiwah (the Great Shaft), Direbo, Laki’ahn, Tahgira, Myst Island (the explorable rainy version), Releeshan, Noloben, & Todelmer (with an added access through its pod). From the Cleft volcano, you can access directly D’ni-Tiwah by jumping inside the volcano
the access is easily reachable by jumping (with a simple run-jump) over the inner fence protecting you from reaching the volcano. The added pod access to Todelmer will be placed inside your pods linking book. The Releeshan book will be located in the City Library. Myst Island will be reachable through the MOUL version of D’ni-K’veer. Once inside D’ni-Tiwah, you’ll gain access to Direbo in different locations enabling you to go back-and-forth through the entire shaft and accessing the 4 remote ages.
About the fan-made ages:The fan-made ages present on the MOUL-based shards are visually more enjoyable than on alcugs shards although the ones present on MOUL-based shards are also present on alcugs shard. URU:CC was developed in 2001 for a public release in 2002, in other words, in a prehistoric era of this numerical age. MOUL-based shards followed the constant evolution of the graphic quality and graphic cards capacities making the play on them more enjoyable with today PCs thanks to their coders. Playing URU:CC (or in this case on DI) in windowed widescreen format and moving your mouse cursor from one application to another is just a dream. You must play it in the 4:3 format to have a great visual experience (in 16:9, everything will look ugly) and your mouse cursor is kept prisoner of the application. You can play, if you have the graphic card capabilities, on DI in full HD (although staying in 4:3 which means you will have 2 huge black bar on each side of your screen) but it will never equals the graphic quality or experience lived on Gehn or TOC MOUL. I even find, personally, that the playing experience on Gehn and TOC MOUL is far better than the one on MOULa itself with the same high end PC specifications. I have to play on an older PC on MOULa to get a really good gaming experience.
What is a fan-made age that fits?It’s hard to answer because it can be viewed with different eyes. Let’s take an age with a gripping storyline, a lot of puzzles, & a great visual look: Adrael. If we stick to URU and the D’ni universe, this age is hard to place in the greater chess board. But is the age worth the visit nevertheless? YES! You learn when linking inside the DRA Office that the DRC wasn’t the only organisation on the trace of the long gone D’ni civilisation. The DRA (standing for D’ni Research Association) a European organisation was also making discoveries about the D’ni. Let’s take another example, in Rahsoo B’ahrotan, you will learn that a D’ni explorer escaped the D’ni Cavern and wandered about in New Mexico at the time when Native Americans were inhabiting that area. Is this plausible? I’ll say YES again. So from these 2 examples, are Adrael & Rahsoo B’ahrotan so far off from the D’ni Universe and URU to be not worth of being included inside a “URU game play”? It always depends on how you look at it. They are not silly ages as their concepts behind are plausible; they form what I would call a part of the expanded universe. It’s for each individual to see if they want to enter in it or stay away from it.
You could also exclude some very well-made ages just because you decide they don’t fit well inside the original storyline... big ages like Elodea or small ages like Relativity. In my mind, they are as important as any more “d’nish” ages.
Maybe do it in 2 times would be a more interesting way: you first concentrate on the original game itself then you come back later on to expand your game play with newer challenges.
How about the neighbourhood(s) and how it can affect my game play?A MOUL-based shard has the same neighbourhood attribution principle as MOULa meaning by this that for every 20 new explorers, a numbered neighbourhood is created. Unless you change to another neighbourhood, it will be your home base. In a huge shard like the Cyan’s MOULa shard, this is a lesser issue as you will eventually meet a lot of explorers visiting public ages. You’ll create bond with some of them and eventually you can join a bigger neighbourhood of few dozen members up to few hundred members. On Gehn and TOC MOUL, this is a huge issue. Let’s say Gehn has 1,000 registered explorers (it’s theoretical). If they are all spread inside numerous neighbourhoods, it makes it really hard to reach a potential threshold of explorers you can actually meet inside the shard at any moment. If for instance at the game opening invite, you see that the shard has 5 active explorers, you will be lucky if you cross the path of at least one of them. This is bad aspect.
TOC MOUL has the same issue but it can be mitigate by the attractiveness of COD. COD attracts everyone, it’s the meeting place in TOC MOUL, most explorers when linking to TOC type “/cod” in their Relto to link to COD. Then they can decide whether they stay there or they join some explorers to go on whatever journey they decide. COD is to TOC MOUL what the public Ae’gura is to MOULa.
DI, on the other hand, is an alcugs shard which makes the issue of numerous neighbourhoods inexistent. There’s only one single open to membership neighbourhood in DI, the “Deep Island Neighbourhood”, that’s it that’s all. Every new explorers logging in DI becomes a member of that huge neighbourhood. Some can see an issue though. Being with everyone, you cannot hide or cannot avoid some bad apples. You can always put them on ignore so you won’t see them as listed online though. You have also less intimacy as everyone using the Neighbours chat is sending messages across the whole server. You have to build a buddy list to have more private chats. You are also subject to more international chat since everyone falls under the same umbrella. You’ll be more exposed to German and French chat lines than on any other servers since everyone can widespread their chat.
A summary of all I said above:I would say there are aficionados of every shard (DI, Gehn, & TOC). Many, like me, just keep visiting these 3 shards getting along with the different vibes of each server. Because each has a different vibe; you always get to play the same core game (URU) but in different way.
Gehn is like a porcelain store: everything inside it looks very sharp & every detail has been worked out, the tune up is done with great care by its owners. You can have a nice exploration time and you cannot be deceived by any non canon stuff because there is none present. Gehn is not very populated and some bugs still remains although not enough to interfere with playability.
TOC MOUL is less rigid than other shards as there are many KI functions coming from the frolic times of Until URU where the fun began. You can see everything on that shard. You can have a complete canon experience but you can also let yourself go on the loose and have great fun. In some occasions, you might have to change your game plan because another explorer is doing some stuff that goes way beyond the normal game, as for example, there are functions to move objects around and to reduce their size. Stumbling on a pocket size Kerath Arch on the courtyard pavement is something possible on TOC MOUL.
DI has the most complex game play of all URU versions as it’s a hybrid between URU:CC’s game play and MOUL’s. You are more subject to annoying bugs that won’t officially be corrected in the near or even far future, the server code has little to no develop these days. You can on the other hand visit every fan-made age available to the public well that’s not entirely true
(*) (see notes after my text). The install is entirely customisable meaning that you can avoid downloading and visiting fan-made ages that doesn’t fit your need or your vision of how URU should look like
(the same applies with MOUL-based shards but the number of fan-made ages available is so low, it’s not a pro or con factor for them).
I think I presented you enough material for you to decide which shard you want to explore. There is not a shard out there that’s better than the others. Each has its pros and cons. If you want my opinion, I prefer DI because I’m an explorationholic (I assume it completely
).
Added information:Cyan official shardMOULa
MOUL-based shardsMinkata Test Shard
The Lost City of Atlantis
(**)TOC MOUL
Destiny
Gehn
(***)Alcugs-based shards:
Deep Island
TOC TPoTS
UAM shard
(****)(*): As I was saying, there are more available ages than what you can find on Deep Island. TOC TPoTS has all the ages available on DI plus some ages developed by the infamous former Peli Team as well as the COD (the alcugs server version of it). The TOC Team is more or less in the continuity of that former Peli Team. If you like pelicans then visiting them is a must-see, if not, you are missing nothing .
(**): there’s one fan-made age available on that server called: “The Maze”. You can also visit it on any alcugs shard.
(***): Gehn runs on its own brew server: dirtsand.
(****): that alcugs server is still running but there is no more maintenance activity done by its owner so it’s like a still shot of Fall 2012; every changes occurred since then has not been ported on that server.
History of URU in a flash REVISED VERSIONDIRT/Mudpie (2000/2001 - 2002)The first beta testings started during that period. At the beginning of the period, Cyan used Plasma 1 Engine (just like the one of realMyst) and finally moved toward Plasma 2 Engine (the one still in use for URU & the one used to build Myst 5 EOA). Toward the end of that period, Cyan opened up a 1st server to authorized explorers called "Choru", followed by a 2nd one called "Ubiru".
URU Live: Prologue (2002 – 2003)Cyan released their game to the general public with the help of Ubisoft. They first created a shard called "Atrus", followed by 2 other playing shards called "Catherine" & "Achenar". There was also a 4th shard called "Rehearsal", its purpose was for testing new Cyan's stuff before they were pushed to the 3 other shards. Ubisoft during that period released the offline game: "URU: Ages Beyond Myst".
Dark Period 1 (2003 – February 2007)That period saw the development of many Until URU servers and the creation of the D’mala (un)official Cyan Until URU shard later during that period. One particularity of those servers was that the subscriptions to any of them were centralized by Cyan. They suspended their activity which might have lead to the emergence of the alcugs servers code which are completely out of their control.
Gametap MOUL (February 2007 – April 2008)Cyan signed a contract with Gametap to make URU available again to the masses. It seems that Gametap decided the contract was not paying off enough for their needs so they closed the game after just a little more than 1 year of existence.
Dark Period 2 (April 2008 – February 2010)That period saw the development of infamous shards based on the alcugs server code like Pelishard. We saw during that period the emergence of the Drizzle tool to add all the available fan-made ages to everyone alongside some goodies like the most important: the offline-KI. Although "drizzling" your offline URU:CC and playing on an alcugs shard is different, they share some similarities. The first fan-made ages addition date (when looking in the Drizzle tool) is in early February 2008 meaning the development of the Drizzle tool and the alcugs code is anterior to 2008 (somewhen before the release of Gametap MOUL)
(Corrections made here, I mostly rewrote the entire paragraph).
MOULa (February 2010 – June 2012)During that time some alcugs shards have been created (UAM in late July 2011 followed by DI in early August 2011) & some have been closed (Pelishard in Fall 2011). MOULa was only maintained by Cyan without applying any modification to its game code.
Cyan’s MOSS (June 2012 – Present day)A lot of MOUL-based shards were created using the open source game code. Some alcugs shards still run and are well-alive. MOULa as it existed from 2010 up to 2012 is non-existent today. We still call it MOULa but the game code has already been modified with fan-made fixes. The shard is still under the sole property of Cyan which can decide what goes or not goes on their server.
That's all! 
