Online gameplay was first found in PC games, but has since found its way to modern video game consoles. The first online consoles were Nintendo's Famicom (NES), via the Famicom Modem peripheral (released 1987), and Sega's Mega Drive (Genesis), via the MegaNet service (launched 1990), though both of these services were exclusive to Japan. The first online console service in North America was the Sega Channel (launched 1994) for the Genesis. At least two other consoles featured online gaming services exclusive to Japan: the SNES's Satellaview (released 1995) and the Saturn's Sega NetLink (launched mid-late 1990s).
Towards the end of the 1990s, Sega created the first worldwide online console gaming service with the SegaNet for the Dreamcast, paving the way in the early 2000s for the online services of the PlayStation 2, GameCube, and Xbox. The Xbox Live service in particular was popular and still is now with the Xbox 360. Meanwhile, Sony's PS2 online service required an adapter and was very different to their more popular PSN network service for PS3. The GameCube also required an adapter and introduced online for some games. Even handheld systems have online, like the PSP and DS. Online gaming is a way to experience games with your friends remotely or other gamers around the world.
While online gaming on PC may vary greatly from game to game, there are a number of online gaming networks that are used for multiple games, such as Games for Windows - Live and Steam. Both has a single friends list that can be used across multiple games. Steam features out of game friends list, chat and server browser. GFW - Live shares user accounts and friends lists with Xbox Live and allows a small number of games to be played cross-platform between PC and Xbox 360. Initially a number of features of GFW - Live was only available for paying users, but they have later been made free.
Xbox Live has a single friends list that is used across all games on Xbox 360, but a subscription fee is needed if you wish to play online.
PlayStation Network has a network wide friends list for each account. It is free to play online on PlayStation Network.
Nintendo Wi-Fi Connection is the name of the online service of Wii and Nintendo DS. It has per-game friends list and has been criticized for needing a 12 digit friend code to add someone to your friends list and general lack of communication with other players. So far, the games that use online mode are Mario Kart Wii, Mario Sports Mix, and Super Smash Bros. Brawl.