Well right now its two weeks, if no prior notice is given, for vacations, school stuff (tests, finals) and the like. Accounts won't be deleted. they will just be deactivated. Deleting accounts is far too cruel and unnecessary. Everyone who is deactivated will be notified by email and they can be reactivated so its nothing to bad I think, just a method of weeding out inactives.
An admin should be contacted through Chatango PMs in order to have an account reactivated. Admins are Cactushh5, xxLonxx, and Kisame88.