Through these fan pages, Blizzard will be able to give a constant feed of news updates and media such as video, galleries, or links. Fan pages are also a common conduit for promos and contests as frequently used by Blizzard partners such as Razer and Figureprints. There are also forums for discussion and a "wall" that allows fans to write on for questions, comments, or anything related to the franchises.
Interestingly, and perhaps owing to its massive player base, the Warcraft fan page has already gained three times as many followers as the other two properties in the short time it has been active. This reflects a similar trend on Twitter, another social networking tool that Blizzard has utilized lately, where @Warcraft has over twice the number of followers of either @Diablo or @Starcraft.