I found out about nextdoor.com from reddit. I thought it was so bizarre people would want their full names, address and sometimes pictures broadcast.
I wanted to see if I could get in with a fake address and name and they do require you to somehow verify you live there (they mail you a card or you link it to a phone number) so I just gave up. Lo and behold I get an email the next week saying my account had been approved anyone because "one of my neighbors verified I lived there".