and Mac!), it's only natural that more niche services would arise; not really to oppose, but to compliment Valve's service. Enter Desura, a distribution platform similar to Steam, save for one important aspect: It's focused on independent game developers.
Primarily, Desura will try to give a home to those games turned away by Steam. Though the service won't just open the floodgates to everything, its creator (and indie mod site) ModDB says it hopes to make acceptance or rejection much more transparent than Valve's process. Desura is described as a community-based service, intended to foster better, more symbiotic relationships between developer and fan.
Desura isn't slated to go live until April, but you can get an early look over at Rock Paper Shotgun.