WoW Insider thinks that this is a fantastic addition. With the popularity of quiz addons in-game and WoW's lengthy past, both in terms of lore and the lifetime of the franchise, this latest addition to the merchandise line has to be a sure-fire success.
Even more excitingly, Blizzplanet reports that "A still undetermined ratio of questions will come directly from fans at some point." So, not only will there be a new way to test out your WoW knowledge with friends, but you can contribute your own question, too. It is not yet clear just how you will go about doing that, but WoW Insider will keep you updated with any new information.