I haven't done PVP. On the PVE server:
1. you can challenge a friendly player to a friendly duel--even somebody in your party. I have done that twice and won one, lost one.
2. If the opposing faction (Alliance if you are playing Horde) shows up in your home territory you can attack them without warning, but they cannot attack you unless you are hostile first.

There are 3 types of servers--PVP, PVE and RP.


The question is not, Can they reason? nor, Can they talk? but, Can they suffer?
~Jeremy Bentham