I can see all sorts of ideas around games in chatroulette space, spreading the word on a cause one person at a time, brainstorming with like minded groups if you could just chat with people who are tagged with an interest, like "Dr Who" or "The Monster Raving Loony Party." Imagine chatting with people at a conference. Demo'ing products. Providing crowdsourced customer support. Think about Good Samaritans -- help strangers who are feeling down.
And want to get really scary? How about live TV that includes "let's hear what random people think about XYZ?" A whole new spin on reality TV. Could be ads you run with the results. How about customer surveys? "Hey, I'm with such and such brand, what do you think about ...?"
Interesting. Can't wait to see what happens.