Gamespot has some wild rumours that Sony is planning on countering the revolution with the PS2. And while they make sure to point out that these are totally unsubstantiated rumours from an anonymous source at Macromedia (?) they are interesting nonetheless. I'm not entirely sure about Sony developing a revolution-like controller and going head-to-head with Nintendo on that front, but the idea of Sony continuing to support the PS2 with fresh content and developing an online service to combat Xbox Live definitely makes sense. A few points:

• 100M users. That is a massive installed user-base. You don't just walk away from that kind of money. You might only get a few million people onto the PS3 in a first few years - a number still utterly dwarfed by the absolute dominance of the PS2. It makes no sense to just leave those people hanging - keep producing games for them and they'll keep buying. Start producing titles to compete with Nintendo's next-gen (party style games etc.) and you could very well steal their thunder.
• Online community. The slimline PS2 ships with the network adapter and a modem built into it. Sure, it probably only costs a few bucks to put it in when you're redesigning the form factor anyway, but it'd make a lot more sense if they were prepping for the rollout of their Xbox Live killer. Free online play, with like quadruple the users, and a new onslaught of games? Yeah.
• Holding down the fort. Recently there have been lots of rumours of PS3 delays, as well as projections of insanely expensive launch prices. In the time between the PS3 being launched and then becoming affordable to the casual gamer, the PS2 can plug a vital hole and keep people from jumping ship to either Nintendo or Microsoft - assuming of course they continue to produce content for the PS2.

Sony has said they would continue to support the PS2 until 2010, which means another 4 years of new content. And while again, it's all speculation, it doesn't seem implausible that Sony would fight on multiple fronts, taking on Nintendo's Revolution with the now low-cost PS2, Xbox Live with its own online service, and of course the 360 with the PS3.

I'm actually a big fan of Nintendo, but having recently picked up a slimline PS2 for Guitar Hero and other party-style games, I'd definitely think twice about a Revolution if suddenly a host of similar games were avaliable on my PS2. And that network port has been just itching to get used.

Should be interesting.