OpenBuilds has supported the open source community for years now and their forum is awesome, a lot of people there with great knowledge and ready to help each other with their projects , build etc
I think is a great option for people looking for a new place to hang out now that G+ is dying.
There is also a 3D printing area at The Maker Forums. (https://forum.makerforums.info) The R7 CNC guys, the K40 community and ChiliPeppr communities have already moved there, and LaserWeb is considering the move as well. It puts all the various maker communities into one place with a unified log in for access to all of them.
@NathanielStenzel You are welcome. I started the forums a week ago, and they are gaining momentum as groups start moving over. I liked the idea of having one place to go under one login, just like we do with G+