I don’t do much gaming these days so maybe Second Life is well known and I just missed it. It certainly is an interesting concept. Instead of paying a service fee, users pay what essentially amounts to a land tax on the virtual land they own.

Become a part of history by purchasing land and developing your own piece of Second Life. The Pricing and Fees are simple; you pay $9.95 a month plus a Land Use Fee proportional to the amount of land you own.

Linden Lab’s Terms of Service agreement recognizes Residents right to retain full intellectual property protection for the digital content they create in Second Life …

The Marketplace currently supports millions of US dollars in monthly transactions. This commerce is handled with the in-world currency, the Linden dollar, which can be converted to US dollars at several thriving online currency exchanges.