minimal PHP + jQ ajax - no database required (file based) http://code.tutsplus.com/tutorials/how-to-create-a-simple-web-based-chat-application–net-5931 http://coursesweb.net/php-mysql/script-chat-simple_s2
Live helper chat http://livehelperchat.com/
phpFreeChat http://www.phpfreechat.net/
websocket http://www.sanwebe.com/2013/05/chat-using-websocket-php-socket http://github.com/PeeHaa/WebSocketDemo http://code.google.com/p/php-websocket-server/ http://www.websocket.org/echo.html
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