Basically - just as Mnemon said - it's a little bit of a mix. We strive to release as many old classics as possible, but sometimes you'll see a newer title here too. It's a matter of licensing mostly - to offer you more titles we have to start with something and then convince publishers to dig deeper and add even more stuff to the catalogue :)
But don't worry, we have some really nice classics from the 90's in the pipeline too :).