How second life gets it right: In-game object creation.
Licensing of work created: "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, including avatar characters, clothing, scripts, textures, objects and designs. This right is enforceable and applicable both in-world and offline, both for non-profit and commercial ventures. You create it, you own it – and it's yours to do with as you please."
The Linden Exchange
And read the Tao of Linden, our work culture.
How second life gets it wrong: Their blog is continually talking of outages and patches and downtime. My guess is they don't do test-driven software development. The quality of the graphics is generally poor, especially when compared to for-pay MMO games like World of Warcraft. I imagine they're struggling with a lot of legacy code. The client is generally lagy and the resultant lag in the user interface makes control of the avatar frustrating.
Having all their employees use an online identity with a last name of Linden is downright creepy.
There is a big opportunity to create a next-generation MMO that has a similar approach but with much better execution. I assume Linden Labs is working on SL 2.0.