One of the fun things about this game, and also for some one of its downfalls, is the fact that the game is always going on. You can get attacked even when you're not online, and you also accrue money when the app is not open, as long as you have more money being brought in from property than is being spent on keeping your equipment in good shape.
Fortunately, this game manages to be fun, without being so addicting that it consumes your whole life like some MMORPG's can. I would highly recommend this game, especially if you are a casual gamer that really enjoys social networking games. Also keep an eye out for free versions of Kingdoms Live that will add "Legend Points" to your account for free!