The concept of trading gigs with another band - say in another city - is nothing new. But what about trading fans? Headliner.fm encourages artists to promote their peers on Facebook, MySpace and Twitter in exchange for return promo to their fan networks. Headliner.fm's platform is designed to keep the trades targeted and even; so the artist is assured of getting as good as their giving.
There are certainly other successful examples of "if you like X, you'll probably like Y" music marketing. Look at what Fall Out Boy has done with it's Ning powered Friends Or Enemies site and community. Of course, like a band that blasts out too much unwanted info, overuse of Headliner.fm has the potential to cause fan burnout. But used wisely, it seems like another worthy tool in the artist marketing toolbox.
Watch a Headliner.fm intro video: