1: (Noun) A topic that's considered to be contrevertial I.E. The second Iraqi war, gay marriage, abortion, etc.
2: (Noun) A store in various malls that sells clothes and tries to target various countercultures (I.E. Goth, Punk, Metalhead, Emo). Over the past few years, Hot Topic has gotten a reputation of forgetting it's core demographic (Urban countercultureists from ages 16-25, who are into music groups that are condisered to be too bizzare and raw to go mainstream, i.e. Danzig, Inkubus Sukkubus, The Casualties) in order to appeal to a new demographic (Suburban youths, ages 11-15, into such musical groups as AFI, Evanescence, Linkin Park who have toned down sounds in their various genres and received mainstream appeal).
3: (Adjective) Something that's not genuine, something mass produced and made to look like it's a part of a counterculture movement.
I hope the second definition is "Fair and Balanced" enough.
1: Do not talk about Ronald Reagan amongst those hippies. He's a hot topic!
2:I got this cute Avril t-shirt at Hot Topic!!
3: Your ICP t-shirt reeks of Hot Topic goth.