What is the use for these abilities?

Question

I can think of two abilities that are pretty much worthless to me:

1. Pressure,I have Kyurem and it says that it's using Pressure
2. Mold Breaker,whenever I face pokemon that are specifically Dragon-type then they use the ability Mold Breaker

What do those two mean,I know that there are more like them in the pokemon world,but if there are more tell me what they do please.

I don't know much much about pokemon games but I can tell you that this is in Black.

Answer 1

1. Pressure causes a move used by your opponent to use twice as much PP.
2. Mold Breaker causes your opponents abilities to be nullified, allowing you to hit Pokemon with Levitate with Ground Type Moves, etc.