Valve Tells Pirates to Walk the Plank
The banned accounts are accused of using either pirated or cracked copies of Half-Life 2 that bypass the game's activation sequence. Despite having a flock of users complaining about lost access in its forums, Valve claims that the number of legitimate users that are unable to play is "VERY small." The accounts, said Valve, were largely from people who tried to "rip off" the game rather than paying for it.
From BetaNews