[ameoba]

Dreamcast had a modem that was supported by very few games. There was an optional Ethernet adapter that's very rare and supported by even fewer.

The ethernet on the PS2 was optional until one of the later hardware releases. Very few games were released using it until after the PS3 had already shipped.

[Jacqued]

Well the Dreamcast was a very early gaming console (1998, even the PS2 is from 2000) so obviously only a few games were developed with online gaming in mind (although a lot of them boasted online features like rankings or bonus content). Still, I have very fond memories of online sessions on Chu Chu Rocket, Phantasy Star Online and Quake III Arena. I believe this predates any other initiative of console online gaming by at least a few years.

Maybe I'm a little biased (because nostalgia, and Jet Set Radio), but I think the Dreamcast was ahead of its time by a margin