It appears Facebook's advertising program will be undergoing a redesign on February 29th — it's rolling out new "premium" ads that show which of your friends liked the advertiser and allow people to comment directly on the ad itself. According to leaked documents posted by GigaOm, the core of this change is that advertisers are now instructed to create ads out of standard posts that they put on their brand page, like a status, link, or photo post. It's very much similar to the way any Facebook user would create a post on their own Timeline, but advertisers then have the option to "promote" that post and push it out as an advertisement.
These ads differ from those that users currently see on their sidebar in that there's an increased social presence — by default users will see which of their friends have "liked" the brand page, and there's options to "like" the specific ad / post and also to add comments to it, just like any other post that shows up in a user's feeds. These changes only occur if at least one of your friends is already a fan of the brand; otherwise it seems that new ads will appear identical to the old style, without a commenting box. Fortunately for users, these ads look like they'll stay put on the sidebar of Facebook, rather than take over main real estate in the full stream of updates. Facebook is quite bullish on how these ads will perform — it estimates that viewers will be 80 percent more likely to remember them.