While you are part of a village, you are affected in several ways:
In order to join a village, you must have enough village respect to join it. For instance, if you wanted to move from Shroud to Konoki, you would have to do diplomacy in Konoki to earn enough respect to join. You must have ten times your base regen to join a village. You must also already have left your previous village.
You can leave your village in your Preferences section. You must be at least Chuunin to leave your village.
Joining a new village will reduce your regen temporarily:
When you join a new village, your regeneration rate will be cut in half for the first day. For the next three days, your regen will be lowered to 60%. On the fourth day, you will receive the full amount of regen that belongs to that village. This will affect ALL regeneration, including temporary boosts purchased through the Black Market.
When a villager wins a PVP battle, her earns 1 VF aka Village Fund. The kage can spend VF on the followings to improve the village.
With the 365 days loyalty, a villager can earn 3 VFs per kill.
Killing an ally from another village at any time will cost your village some of its Village Funds.
A village loses 1% VF each day if it is in war, and in war, the village that wins is rewarded with a net sum of VF (20,000 total possible) at the end of war.