You control the characters 100% and you can create, buy/sell items and land. You can also interact with and share items. I just signed up for the free account to mess around in there.
Interesting but far too complicated for me. I'm not even quite sure that I understand - it seems like one of the major objectives is somehow creating value within an virtual economy that includes tender convertible to and from "real" money. I guess like Tom said it seems to be a rediculously interactive (or maybe dorkier) version of SimCity.
Unless it will make me rich or get me laid, I don't know if I'm interested in a second life.