Alot of times when they don't call back, it means they found something on you. I.E. pics/statuses of you or about you on Facebook with bad references like smoking, drinking, or cursing. Seriously I'd know this, my dad works for the Florida BAR and they check everything about you when hiring. Now, take this with a grain of salt considering you probably aren't applying to the BAR. But still, do you have a criminal record? Do you look grimy? Long, unkempt hair/gauges/tattoos that places might not like?
What ever happen to no discriminating.