According to New World Notes writer Onder Skall, the game has around 300 players. Our experience with the world proved it to be expansive; upon teleporting to the start of the sim, we stepped out of the overlooking portal room and had an exhilirating view of the massive city on our equally massive fall.
As to whether or not the game has the blessing of IP owner Square Enix, not even the creators are sure. While they do the developer a service by providing a high quality sim that promotes the Final Fantasy brand to great success, they are making money (however little it may be) off of the brand. SL users can click here to go to Midgar directly.
[Via Second Life Insider]