Thanks, Facebook for stifling my political expression and putting a limit on my freedom! And how many groups is too many? I don't know. Facebook didn't tell me that in this helpful popup message. I just tripped the secret magic number. When I looked further, I found that I'm a member of 301 groups (joined over a five year period). So the cap is 301? Whatever. I found a group for people in my situation called I Have Joined Too Many Groups, but I couldn't join it. Because I am a member of too many groups. In conclusion:Dear Facebook, I think I'm a member of too many Facebooks. Bite me.