The Meaning of Life, the Universe, and Everything.
I'd post it on Server Help, but that seems to be technical stuff only.
Basically, my server idea is: players select out of 4 already pre-made factions to join and play is. The only problem is how to deal with traitors, people who wont cooperate, grief each other? Would this be too much of a hustle to enforce? Because if factions are simply fighting within each other, they wont get far.
Get some server staff to act as high-ranking members of the faction, primarily to catch problem players, and offer rewards of some kind to encourage players to stick with a single faction. It would also be best to try strip as much stuff granted by a faction as possible if they get kicked out/quit. Just stripping items can be kind of iffy, just because you'd be able to keep them in chests scattered around or give them to other players, but say, if they get awarded a plot of land, it would be common sense for the faction to take the land back, as well as anything on it. But the most important thing about this is that you absolutely need competent staff, who understand that admin abilities aren't toys for them to do as they please with, who are able to withstand insults yet take actual criticism into account, and who understand when you need a light touch or to drop the hammer.