There have been several clever Facebook promotions hatching lately. Following are two examples which go beyond “branded entertainment” and begin to drive revenue. Both rely heavily on the social graph.
IKEA uses Facebook (and photo tags) instead of traditional media to promote new store opening. Read more
Intel aggregates demand

Read how this promotion works
Oh, I almost forgot. Thanks to Twitter, a friend could be an ad too. The game here seems pretty simple: find a person of influence and get him or her to promote your message to their followers. Ad.ly is trying to make this tactic into a service. Read about it.
In the very near future, I foresee sports and entertainment properties selling tickets via promotions like these. Stay tuned.
Did you go to the show in Las Vegaslast spring?