Sony has had to sacrifice a lot with the PS3 in order to push sales forward and overcome competition. Since the console launch, prices have been cut prematurely, the processor has been given an overhaul, among other number of tactics and re-bundles. In a bit of backwards thinking though, Sony may decide to do without a feature that has been attractive to many previous PlayStation owners: backwards compatibility. If recent rumors are to be believed, Sony may stop offering any models of the PlayStation 3 that are able to play PS2 games.
The reason behind the move has been justified with claims that the increasing number of PS3 titles should more than compensate for the lack of backwards compatibility. Realistically, it is unlikely to impact sales - after all, why would someone buy a PS3 with the sole intention of playing PS2 games? Consolidation in the console market might be an argument opposing this, but I doubt it has a big enough impact to worry Sony, especially now, after the demise of the HD DVD format, the PS3 becomes an even more attractive option with its built-in Blu-ray player.
It was just last month that the PS3 outsold the 360 month to month for the first time ever in the US, even coming very close to the reigning Wii.