CodeCanyon - Facebook Viral for Fb Pages Tabs v1.0 | 3,66 MB
Did you ever dream to get a viral app fully integrated to the Facebook experience? You’ve got it. With this app you can let you users connect with their Facebook account before being able to access a reserved content (video, article, download link...).
But that's only one part of this app can do, here are the most awesome and marketing oriented list of features...
DEMO:
http://codecanyon.net/item/facebook-viral-for-fb-pages-tabs/5125922