I'm usually iffy on using games for education, because usually the people trying to do it don't have the first clue about what games really are. But something like this-- asking a beginning writer to use their game knowledge to make a guide or analyze gameplay-- seems much more well-founded and beneficial. And if all these librarians are part of the nine million people who play WoW, then this definitely seems like a great idea-- use common ground to help teach reading and learning skills.
Of course, that doesn't necessarily mean WoW Insider should be bookmarked on every library computer (although, now that it's been mentioned...). But it's cool to see librarians using their knowledge of Azeroth to help teach real-world skills.