In DAoC (Dark Ages of Camelot) the realms are more fighting with each other, not talking like in AO.
In Daoc the realms are attacking each other and taking over parts (look at http://www.camelotherald.com/realms/ and click on a link).
In AO (almost) all PvP are in arenas and places like that.
I will maybe change to DAOC.