Wikipedia
PlayOnline is an online gaming service created by Square Co. (now Square Enix) in January 28, 2000, and has been the launcher application and Internet service for many of the online PC, PlayStation 2 and Xbox 360 games the company publishes. Games hosted included Front Mission Online, Fantasy Earth: The Ring of Dominion, Tetra Master, and the Japanese releases of EverQuest II, Dirge of Cerberus: Final Fantasy VII and JongHoLo.
The service hosted hundreds of thousands of players at its peak, and was one of the first cross-platform gaming services. It was shutdown during the 2011 earthquake in Japan for twelve days. The platform was also subjected to denial of service attacks and players attempting to cheat who were subsequently banned.
Starting with Final Fantasy XIV, Square Enix began moving their online games off of the service, and many of the social networking features the game was released with failed to catch on, with the service being described as "clunky". The termination date of service for Final Fantasy XI and PlayOnline for PlayStation 2 and Xbox 360 was March 2016, with only the PC version of Final Fantasy XI still supported.