Just because you folks have a hard time handling the intricacy and sheer massiveness of tags/genres, doesn't mean it isn't of use to other people seeking out a specific style/sound. Quit your bitchin'. 
Chamber pop is actually a pretty good genre name. Chamber music is a form of classical music, written for a small group of instruments which traditionally could be accommodated in a palace chamber. Most broadly, it includes any art music that is performed by a small number of performers with one performer to a part. (that's straight from Wikipedia--and from my Music 101 textbok from my freshman year of college) Chamber Pop is "pop" in the sense that it is not "art" music (i.e. Beethoven and Co.--you know, music that takes prodigious skill to perform well). But Chamber Pop is not "pop" music in the sense that it's mainstream and should bear the name of the producer instead of the band. Chamber Pop is group-oriented, with each instrumental part possessing some significant individual value, hence the "characterized by an infusion of orchestral arrangements." The ignorant "I'm-not-mainstream" Indie kids sincerely think they don't listen to Pop music. Idiots.
Some of these bands are amazing, but to claim they belong to a coherent 'movement' is absurd. It feels like the work of some self-aggrandizing journo, desperate to take credit for discovering a new 'scene'.
If anyone's looking for new chamber pop music to check out, look no further than FUN. Members of The Format, Anathallo, and Steel Train. You can get a free mp3 right here: http://www.previewnewmusic.com/fun/