Wired has an interesting article describing the "guerrillas" who have invaded this week's MacWorld show in New York to taut their favorite software package (Final Cut Pro) as a mechanism for revolutionizing film.
What surprised me was that there are 27,000 members of the FCPUG (Final Cut Pro User Group) in LA alone! I know they're into film out there, but wow!
There is also a parent organization now of Final Cut Pro user groups called FCPUGNet (the Final Cut Pro User Groups Network), although their site doesn't appear to have been substantially updated since April.
Still, if you go to the LA-FCPUG site, you will get a good idea of the kind of community that has been formed around this package.