This is an interesting link: How to distinguish brown dwarfs from planets.
http://encyclopedia.lockergnome.com/s/b/Brown_dwarf#Distinguishing_light_brown_dwarfs_from_large_planets
Honestly, this info is causing me to have to redefine my terms. I pretty much always thought that a categorization as a star (which I believed included brown dwarfs) required ongoing fusion. But according to this, apparently not. Then again, they don't seem to be sure themselves how to classify it, since one minute they refer to it as "sub-stellar" and another minute they do call it a star. Frankly, without having ever undergone fusion, I would've called it a heavy planet. But I can see how the fact that it's uniform like a star (not much difference in chemical makeup based on depth) takes it out of the planet category too. Interesting. For about ten minutes. Think I'll go back to devoting my attention to the cool stuff like black holes/quasars/pulsars ;)
Qwinn
Its the lack of defining characteristics and a large statistical base to operate on.
Same issue we're having with planets and arguements on whether Pluto should be downgraded or Sedna upgraded (etc)