People in tech blogosphere are aware of this for sometime now. But I still thought it is worth posting it here in this blog. David Weinberger writes on Huffington Post
The new ad infrastructure enables Facebook to extend their reach onto other companies’ sites. For example, if you rent a copy of “Biodome” from Blockbuster.com, Blockbuster will look for a Facebook cookie on your computer. If it finds one, it will send a ping to Facebook. The Blockbuster site will pop up a “toast” (= popup) asking if you want to let your friends at Facebook know that you rented “Biodome.” If you say yes, next time you log into Facebook, Facebook will ask you to confirm that you want to let your friends know of your recent rental. If you say yes, that becomes an event that’s propagated in the news feed going to your friends.
