From their site: Lingr is an open community of chatrooms. You can chat about anything you want, in public or private rooms. No account is required, and no special software. Just choose a room and start chatting. You could use the Lingr API to write an application to monitor activity in chatrooms and notify you when your friends are chatting (whoops, we already did that), to create a chat-bot that automatically responds to other chatters, or anything else you can think of.