Sort of, but twitch is primarily used to record gameplay. Unlike tinychat, you can notify people on youtube that you are on. Basically twitch is more spectating than actual chatting.
Just wanted to elaborate on FOIL's post Twitch, unlike YouTube and other such video sites, allows you to watch the person play the game live and give them feedback and ideas in Twitch Chat there and then, rather than having to wait a day or two for some of ur viewers on YouTube, etc. Its kinda like tinychat in that sense, altho tinychat isnt really the ideal place to stream a game to other people. Also if you subscribe to a Twitch Streamer, you get an e-mail notification saying when theyre streaming live. wagon