"Flash-based multiplayer platformer where users could edit the level" http://everybodyedits.com http://everybodyedits.com - it's got a lot better recently now

"Flash-based multiplayer platformer where users could edit the level" http://everybodyedits.com http://everybodyedits.com - it's got a lot better recently now there are private rooms (although yes, that does mean it's a different concept now)