SF3 isn't popular because the CPS3 was expensive due to being way ahead of it's time and rare as hell in arcades and being a Dreamcast only game. The characters didn't bring in casuals either like how Blanka and Guile did.
Also saying it's not popular because it was too technical is wrong since if you play SF3TS OE you still see a bunch of shoto scrubs and mashy Chun lis. The Alpha games were also much more technical than SF2 yet all 3 were popular.
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http://i43.photobucket.com/albums/e373/Gaiash/KumaVsZangief.jpg
LOL!!!! I hope that's a joke....names don't get more n00bish than that