Way back I posted about the potential of in-game advertising and other forms of virtual marketing. Now, more than two years later Valve (producer of the excellent Half-Life 1 and 2 engine) catches onto this very same idea and has introduced a beta version of Counter-Strike 1.6 that includes advertising. They also think that loads of kids spend more time gaming than watching television. Their beta only shows Valve related ads at the moment, but will include other options once released.
These screenshots show the ads on the walls of the play scene, and in the hud (heads-up display) of the game. Care to try it yourself? Instructions are available here at the Valve Developer Community.
I wonder when Blizzard will introduce in-game advertising in its current hit World of Warcraft.