If you note, laugh-tracks are fading away-- the best modern comedies don't have them at all. And The Big Bang theory is full of it (as I mentioned, I've only watched the pilot, but it was all over the net a while back.)
See:
http://www.youtube.com/results?searc...ugh+track&aq=0
http://www.google.com/search?hl=en&s...AAAKoEBU_QKgHr
and especially
http://www.youtube.com/watch?v=0KX9alvBit8
(Language NSFW)