Facebook thinks that your News Ticker isnt crowded enough already with the crazy tags you get everyday and the huge load of useless posts, so they have decided to include Ads in the ticker now so you wont be bored due to a lack of ads.
Facebook will show these ads as Sponsored Stories and they will appear in the Facebook Ticker which shows activities such as users listening to songs, reading news articles, leaving wall posts, or adding new friends. So the ads might appear in the form of “Your Friend (Insert Name Here) Is Playing Bejeweled Blitz”.
If you were thinking of leaving facebook, you will now have one more reason to do it.(Techcrunch)