Beginning in January 2012, Facebook's "Sponsored Stories" ads will find their way into users main news feeds. Previously relegated to the sidebar Ticker, these ads are created when a friend or user interacts with a business by liking or commenting on its pages. TechCrunch reports that the ads will only appear once per day and that users will not be able to opt out of them, though each ad can be individually hidden as it appears in the feed. The ads won't appear on mobile versions of Facebook at launch.
Sponsored Story ads will look similar to what you're seeing above — virtually identical to regular stories from actual users, but with a small "Sponsored" indicator. They'll be relevant (and therefore valuable to advertisers) insofar as they will only appear if the ad content is already socially linked to the user by a friend or liked page. It will be the first time that ads have ever appeared in the main news feed intermixed with more genuine social content, which will make them lucrative for Facebook but potentially annoying to users. So it goes.