I've never had a FB account, never thought I missed anything. But, there's a Buy-Nothing group I want to join, and they are on FB. I admire the concept of Buy

I've never had a FB account, never thought I missed anything. But, there's a Buy-Nothing group I want to join, and they are on FB. I admire the concept of Buy-Nothing, but I abhor FB and am not going to make an account to join Buy-Nothing. Even if I were to start a new Buy-Nothing group, FB provides the most reach because it's pervasive and probably easiest to use, and one can be tagged with one's location. Mailing lists don't thread well, GoogleGroup is a dumpster fire. What other tools can I use to build a like-minded community for good?