From the PlanetXbox360.com feature list:
"Online gaming on consoles may be popular now, but it wasn't always this way. Systems like the Sega Saturn, Sega Dreamcast, and the original Xbox attempted to bring online gaming to the masses, however, they did so with decent success. The Xbox almost made it happen, especially with heavy-hitting releases like Halo 2 that persuaded gamers to invest in the LIVE service. It wasn't until the launch of the Xbox 360 that gaming online really started taking off. Nowadays, whenever you purchase a new game, there's a huge chance that it features a mode allowing you to play with or against real people (Army of Two - perfect example of teamwork in gaming). Of course, there are still many titles available that don't let players interact with others across the globe. Normally, this is due to many factors, like meeting a deadline or not having enough manpower. In these cases, it's understandable, but there are instances where specific games would have been better with the addition of an online multiplayer or co-op mode."