I'm banned from Quora. I signed up to post an answer to an astrophysics question that hadn't been answered; I spent about 2 hours fully researching and sourcing my answer, and got several words of thanks and a decent number of upvotes.
But because I didn't use my real name, I was blocked. As a teacher with a (un)healthy does of paranoia, I never use my real name on public forums, just in case; I believe (and Quora disagrees) that whether what I write is worth reading depends on what I write, rather than whether I used a real-sounding name. I switched to better places like physics.stackexchange instead.
I'm glad now - I feel quite vindicated!