Well I think that each corresponds mainly to which buildings or units get built. If you check the crusader build files they list all the strategies and theres a number there w/c acts like a percentage I think of whether or not the faction builds this building. Like defensive factions tend to build up fortifications before anything else, devout factions will tend to build religious buildings and crusader factions will build up crusader buildings and send out crusades.

Just my 2 cents,
Gilbert de Clare