Ultima Online spent years developing a system that was destroyed by players
MMOs as virtual worlds are really hard. Red Dead Redemption online has all the great graphics, but play is mostly people randomly killing other people.  No plot. This is a big problem with MMOs - big working worlds can be built, but mostly people just kill each other. Look at the success of Fortnite - 8 million peak concurrent players.<p>Second Life has a functional economy, but no NPC ecosystem. The economy is driven by land ownership and fashion. Second Life has landlords, who pay money to Linden Labs for land and get a bulk discount, then rent it out. They have most of the problems of real landlords - collecting rent, handling evictions, dealing with tenant complaints and tenant disputes.  Most of the administration of Second Life is handled by landlords. The biggest operations make US$ 6-7 figures this way.<p>Fashion is a big deal in Second Life. There are designers with followings. Fashion shows. Women are in the majority. This is entirely player based - players are buying from other players. LL takes a cut when converting from Linden dollars to US dollars, but it&#x27;s under 10%.<p>Objects in SL have privileges, but not quite like files. The privileges are Copy, Mod, and Transfer. This is key to making the economy work. Owning an item with Copy privilege lets you make more copies, but you can&#x27;t give them other people. With Transfer privilege alone, you can give or sell the item to others, but can&#x27;t make more copies. Items like furniture and vehicles are usually Copy, no Transfer, so you can buy one chair and set up a room, but not set up a car dealership. Clothing is usually Transfer, no Copy, so only the owning avatar can wear it, but you can sell it at a rummage sale.  Anything which is both Copy and Transfer can be duplicated and sold. All this is server side, so it&#x27;s hard to break the protection.<p>SL now has a NPC system, &quot;animesh&quot;, but, as is typical for Linden Labs, they just implemented it and gave out a few demo objects. Everything else is up to the users.<p>SL runs about 40,000 concurrent users, which would place it at about #12 on Steam if it were on there, around where GTA V is on Steam.