ok...never thought of BMX as mt. biking; skate parks and prepared tracks are the mainstay of the BMX, much less so the trails/forests, etc.
definitions are going along OK at first, but: WTF is 'free mountain biking'? is this a reference to freeriding? if so, that definition is WAY off! freeriding is extreme, requiring lots of skill in near-impossible terrain, and 'staying close to the ground' is not even an issue. freeriders are the pioneers of 'big air'!
trail mountain biking is in no way restricted to low-slung frames or small wheels; it is the largest segment of mt. biking out there. the bikes are not special as compared to others; in fact, most trail bikes are the standard against which other categories are measured.
alison may be a frequent contributor, but she doesn't come across as someone who's involved in, much less passionate for, the sport.