check responsive design on this website tool

http://www.responsinator.com/

New Technologies 2013:
http://conceptboard.com or http://beta.mural.ly

http://knockoutjs.com, Query ui, mootools, Kendo ui

http://www.servicestack.net/

www.tokbox.com, and HTML5 players http://videojs.com/, http://mediaelementjs.com/

http://www.frozenmountain.com/websync, signarR, http://pusher.com, socket.io/ nodejs, firebase

http://call.jsonlib.com/
online chat system (olark, snapengage)