#0 - Feb. 3, 2010, 10:33 a.m.
The app lets you create a custom feed of your characters' activity straight from the Armory, share it with the Facebook community, and view your friends' characters — all on Facebook. Once you’ve set up the app and linked it to your account, your Facebook identity will be associated with up to five characters of your choosing, and the app will generate automatic updates for your accomplishments, such as level gains, achievements, boss kills, and so on. For more information on how the app works, along with some helpful privacy tips, check out the FAQ.
http://eu.blizzard.com/support/article.xml?locale=en_GB&articleId=41990&pageNumber=1&searchQuery=facebook