I joined the AEA Learning Online community along with one entitled Substitute Teaching. I'm hesitant to join additional communities because I believe that Google announced that it will be shutting Google+ down in the not too distant future. (April?)
I just learned about goggle+ and was looking forward to using this media with my classroom students and their parents. It doesn't look like that will be happening now if they go through with the shutdown the first of April. Makes me sad.