Years ago a new phenomenon in social networking came to the United States. It was called Cyworld. The premise as I remember it was to have users sign up and build a profile (alah facebook, myspace). The unique feature was the ability to customize your own personal virtual 'room', which was essentially a cartoony box that acted as the center piece for your profile. It was unique and people would comment on your room, could send you gifts, and do all sorts of other things I really do not remember now.
The kicker was these objects had to be purchase using real money. Not directly of course, but by paying x-dollars you could buy virtual currency (acorns) which was then used to purchase objects, people, animals (dolphin anyone?) for your room. Want to know what happened? See the picture below.
The idea just did not catch on in the US. Not too surprising if you ask me. I played around with Cyworld when it first came to the US and was in trial mode and could not see myself paying cash money to pretty up a page. Especially since there are a number of free alternatives.
Interestingly enough it is HUGE in Korea. The Korea CyWorld cite claims to have 25% of the population as users. Considering South Korea has 48 million people that is a significant following.