Unsee - The ability to open a chat session and message then delete it from history forever just like tlk.
Anologue - Disposable online chat.
Meet in Chat - Meet new people. Have fun sharing photos.
JabbR - A chat application built with ASP.NET and SignalR.
nohistory.chat - nohistory.chat - free, anonymous and disposable web chat.
EchoWaves - Opensource Social Group Chat written in Ruby On Rails