It's all a bit similar to Xbox Live in that you can download playable demos and trailers of upcoming games for free.
Demos available to download at the moment include Formula One Championship, NBA 07 and more importantly Motorstorm and Resistance: Fall of Man.
If you're one of the ten people in the world who owns a TV good enough to do Blu-ray justice, you'll also find a bunch of trailers up there for your viewing please.