My Groups and Communities
(Founder, except where noted).
* I would like to THANK all other admins to help managing them. The large portion of the groups' success is in our collaboration. 
1. Professional communities:
 (Update 6/9/20 While many were founded by me, later work is shared or taken over by other trustworthy admins and moderators. We also try to back up each other groups, so you can find some useful groups that were founded by my friends/admins/co-admins.. 
2. Hobbies and interests. Social clubs (Bay Area & North Carolina RTP Triangle region)
3. Ethnical Communities
Russian Jewish Communities in Bay Area: 
Armenian Communities: 
And many more :)
PS: And many more to come, LOL