Folks are saying -

Django-style gypsy jazz is an active style played by many young musicians who truly capture the spirit, and sometimes make innovations within the form.
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One of my oldtime pals is a "gypsy jazz" guy of some note. Will Patton, an extraordinarily talented mandolin player (and bassist, guitarist, etc.). He has several CDs out, if anyone's interested.

I asked him why the label of "gypsy jazz" when what they're playing is traditionally known as swing. He didn't really have an answer. It's just what people are calling it.
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Well, "swing" can mean a lot of styles of music but "gypsy jazz" = "in the style of Djano Reinhardt" presumably.
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Yeah but Django played in a style called swing in its day. It wasn't considered "Gypsy" anything.

Anyway, if anyone's interested, check my friend Will Patton. He was the first cat I ever heard play real bebop on a mandolin, years before I'd heard of the others with bigger names who've done it since, and he's doing it still. He's also way into Brazilian music. A real master.
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I play with a gypsy-jazz group about six times a year as an accordion player, subbing for either the violin player or one of the guitar players. In my mind, what makes it "gypsy-jazz" is not only the obvious Grappelli-Reinhardt association, but also the absence of drums, being all-acoustic, the always-present rhythm guitar due to having two guitar players, the two-beat bass, playing many of the pop standards from that era, and emphasis on swing chord changes as opposed to reharmonized bop chord changes.

I've often wondered whether bluegrass preceded Django, although I somehow doubt that Django actually heard any bluegrass until much later if at all. There was a group that Buell Neidlinger led called "Buellgrass" that played a very progressive cross of gypsy-jazz and bluegrass, and they were contemporaries of the guys who played the music that became known as newgrass. The band included Richard Greene on fiddle, Andy Statman on mandolin, and the late Peter Ivers on harmonica. I think their record is still available at Buell's website, and they also did a pretty good record called "Swinggrass '83" which was their only major-label release.
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Django preceded bluegrass, of course. Bill Monroe debuted the style with the Grand Ole Opry in 1939.
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Nate, do you know if there is any admission by Bill Monroe of having heard Django prior to 1939 (most likely on record than in person)?
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It's probably only Gypsy jazz by association. After Django the style was pretty much dormant until there was a movement in France among Manouches or Gitanes (I could never figure out whether the two terms refer to different groups) to revive the form, so most of the players happen to have been "Gypsies."

The recent Django bio is pretty informative, and this page is interesting:

http://www.rootsworld.com/rw/feature/gypsy1.html
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I kind of wondered myself about the need for the term "Gypsy Jazz" until I discovered that there was this huge Django-obsessed subculture out there, complete with Trekkie-like conventions. There's a documentary out about this phenomenom called Djangomania! VIBEr does a real good job of describing this little sub-genre that has sprung out from this. I would imagine that it's favored, in part, by people who like bluegrass but don't always like the hillbilly associations.