Nowadays, it is much more common for a company to hire community managers to act as intermediaries between developers and players. Games are more complex and it is not just a couple guys in their basement anymore. Think about the opportunities for miscommunication if every developer on a large team posted their opinions on a game forum. It would be anarchy and the game studio would constantly be clarifying statements and putting out fires. When you look at that way, it becomes obvious that community managers serve an important function. Not that every gamer will agree they are necessary. As developers became more removed from gamers there's been an increasing amount of disdain for community managers and the forums they moderate. Over the years, several games have had bad situations on their forums that have some companies wondering if forums are even worth the trouble.
I guess it's no surprise that I'll use World of Warcraft as the example of a forum that went too long with proper moderation. The sheer magnitude of the game's success quickly created one of the world's largest gaming forums and Blizzard was ill equipped to handle it. The ratio of community managers to actual posters was incredibly low and you could see this slowly have an effect on their sanity. One infamous example is the story of Tseric, who eventually lost his cool against a pack of trolls on the shaman forums. I think this situation finally convinced Blizzard they had a problem on their hands and I have noticed an increase in community managers since then. It's still not the best place to find insightful discussion about the game but it has greatly improved.
If you want to see heavy-handed moderation then you don't have to go further than the first wildly successful MMO in North America. EverQuest had growth that was much slower then World of Warcraft and as a result, it allowed management to better judge how many moderators they needed. However, their moderation policy has always been much stricter then World of Warcraft. Some people like having a clean forum that avoids a lot of the drama and rudeness that tends to develop around passionate MMO players. Others though find it too sterile and make use of fan run forums so they can be a little more forceful in their opinions. This unfortunately makes it much harder for companies like SOE to do damage control when an incident occurs.
Some companies see how hard it is to walk the line between censorship and promoting active discussion and decide to do without official forums. Instead, they provide tools for fan sites and make use of their forums. This way a single project lead can post upcoming news on several fan sites and the company does not have to worry about hiring forum moderators. This prevents players from developing resentment towards official community moderators and neatly bypasses any censorship issues. Mythic has used this method with Dark Age of Camelot, though they supplement the fan site communication with an official newsletter. It apparently works well enough that they felt comfortable using the same system for Warhammer Online.
There are still major issues that can develop by not having official forums. Mythic found that out the hard way with the European open beta for Warhammer. The publisher Mythic was using to release the game in Europe was having some technical problems with the account authentication process. Unfortunately, it was hard to get information out on what was causing the issue and the fan run forums filled up with a lot angry inquiries. Since the European publisher did not have the same relationship with the fan sites as Mythic, they had problems publishing updates on the issue. This caused a delay in the communication pipeline and left players in the dark regarding the status of the open beta.
I think the situation perfectly highlights how MMO players react to having their communication lines with a game cut off. It is a unique situation since most other video game genres don't have this problem. However, since MMO players pay a monthly fee they tend to see their game as more of a service then a product. Thus, they expect a slightly higher degree of customer service. In addition, game worlds are constantly changing and players want to insure that their game does not evolve into something they don't enjoy playing anymore. I believe these two reasons are the driving force behind player behavior on MMO forums. Companies should keep that in mind when designing their forum strategy. Whether they go with fan based or official forums they need to keep in mind that players just want to be involved.