Ten Ton Hammer managed to track down EverQuest and Vanguard: Saga of Heroes designer Brad McQuaid for an article-style interview about managing fan expectations in order to avoid post-launch disappointment.
(I definitely got caught up in my own hype with Vanguard,) he admits.
In retrospect he offers this advice to developers: (I think it's very important to hype only features that you are positive will make it into the game. As development progresses one becomes surer of what will and will not make it into the released game. So, over time, you can reveal more and more about the game with confidence. That said, I think a certain degree of fan-generated over-hype is inevitable.)
And fan over-hype can indeed be a problem. With any MMO, there are certain well-informed fans who emerge as evangelists for the game, talking it up and defending it on official and other discussion forums. Do these evangelists, who think the game and its developers can do no wrong, affect the perception of other fans, making it more difficult for developers to keep expectations in line?
(It depends on how the situation is handled,) says McQuaid. (The developer can help manage expectations not only by not over-hyping themselves, but they can also reach out to these zealous and high-visibility fans and work with them. If the zealous fan is really working hard to be visible, and to hype your game, then I think it's well worth it to reach out to them on a personal level, shaping the relationship such that he or she is indeed a boon and not a detriment.)