A constant issue the WoW chapter has had, in all of its iterations, is that almost everyone played WoW before they found CotP. Therefor everyone's characters are always on different servers, and often people don't want to move servers for sentimental, monetary, or other reasons. The new Communities Feature helps alleviate this issue. It allows members on different servers to join the 'community' and participate in community(guild) chat, group together, and do calendar events.
I opted for the WoW and Faction specific community over the B.net one, mainly to allow people to step away from t