Along with more traditional virtual worlds, The OpenSim community is quickly developing on Koinup. So I'd like suggest you to join some group related to Open Sims.
At first, I invite you to have a look at Cyberlandia
Cyberlandia is an italian grid, based on the Open Sim platform. It's quickly growing and it is one of the most important destination for metaverse people from Italy
Then, I invite you to have a look at Avatar Hangout
Avatar Hangout is one of the most structured and well done OpenSims. Enjoying this place (and group) you have the clear impression the Opensource movement is doing great things!
Enjoy these groups now!