Real porn doesn't feel real, because they are all actors. Drawn or 3D-rendered characters feel more real because they aren't real so they can be what they are supposed to be. If that makes any sense.
First it was porn comics and then 3D videos. While looking for those on porn sites I discovered some gameplay videos of visual novels and stuff. And then I found some site where you can actually download those games. And then another site and so on.