Activision won't be the first publisher to make its games available on Steam. Ubisoft, the company behind Prince of Persia, Myst, and Tom Clancy titles is also on board with Dark Messiah of Might & Magic, which is scheduled to hit Steam later this month. Majesco Entertainment also made Bloodrayne, Bloodrayne 2, and Advent Rising available on Steam last month.
In related news, Valve recently kicked off a beta version of a dynamic pricing scheme for Counter-Strike: Source. The scheme varies pricing for the game's various weapons based on market demand, and prices are updated every Monday. It's an interesting approach for a first-person shooter, and one that has predictably polarized the always vocal Counter-Strike community. A list of weapon prices and projected changes for next week is available here.