Guild Halls are a big part of the feature list for Guild Wars 2‘s first expansion, and with good cause. The ongoing livestreams of the week have shared a lot more details of how the feature will work for players; you can watch the saved streams yourself, but if you don’t want to wait through two hours of video, you can also take a look at Dulfy’s handy summaries of day two and day three‘s revelations.
The short version is that the halls will be collaborative efforts, requiring a concerted gathering effort to develop the hall slowly over time. Scribes also can help make decorations as a full crafting profession; the craft can also make backpacks and stat-boosting scrolls. There’s a lot of information, but it’s important reading for those looking forward to the halls.
Equally important is the revelation that players looking forward to raiding in the expansion will want a full set of Ascended gear for the ending of a given raid. That’s what it’s balanced around, specifically; there’s no Agony-style mechanic. You can try out the raid during the coming test weekend; some discussion has already erupted regarding player ability and accessibility of raids.