most 'poppers' are butyl, not amyl nitrite (now, anyway). nitrite, not nitrate. i still get that confused.
i'm guessing the name poppers comes from the old amyl nitrite, which was apparently prepared as a glass ampoule inside a cotton wick, or something like that. there's some in fear and loathing in las vegas; they call them amyls, and they break them and breathe the vapor. the original use was for angina; they're also an antidote for cyanide, apparently.
poppers have the distinction of being the only drug ive ever found on the floor at a party, other than some ephedrine. other than ravers, who will abuse anything, i think it's mainly a sexual drug (primarily but not necessarily gay); the muscle relaxant effect apparently prolongs orgasm. there is one other significant use; they're fun with k. don't ask.