Are there any other games with a fluid valuable economy like RuneScape?

The economy of RuneScape truly impresses me. It's used to trade in many different forms like prisons, cartels, anonymous trading as a BTC substitute, or even simply a job for someone not too well off.

Jagex is so against the trade of gold, but I'm not sure if they realize they're saving the lives of thousands of people. People in places like Venezuela are able to work on RuneScape to make decent money that they aren't able to make elsewhere in their country.

It's so amazing, 30 seconds to sign up, 8 minute Tutorial Island, and you're free to earn REAL WORLD MONEY enjoying a video game. It's very easily trade able and with one visit to Sythe 10 minutes later you have gold or sold gold.

I honestly can't think of another video game economy even close to it. It's one of the worlds most played games, with an OPEN ECONOMY. Are there any other games like this? I'll be very sad when gold loses its value, or RuneScape dies.