According to this Frommer's article, you can no longer be bumped after you have been seated on the airplane. However, you can still be bumped if you are in the terminal. Compensation has been increased for delays in travel plan.
I've been bump at least once. On several other occasions, they asked for some passengers to voluntarily give up their seat in exchange for voucher for free flight, often with some restrictions. If no one volunteers, they may sweeten the deal. If tempted, I suggest negotiating.