Lipstick Alley is a large active forum catering to black women. It had, or perhaps has, a Back Alley. This announcement from 2018 describes it:
“The Back Alley forum is the only place where beef is allowed. It was created to try to contain those people who are unable to control their rage at whatever has angered them on the main forum. It is the cesspool of LSA, so if you decide to engage, don’t complain. The only things that are not allowed back there are posts referencing a member’s race, sexµal orientation, ethnicity, disability or religion.”
Another announcement from that year limited access to members of 30 days duration and with at least 50 posts. I don’t know if it is still extant.
How on earth did a mu end up in that word?
I see it in the original statement too, so it’s nothing to do with copying and pasting it. That statement also appears to be from 2018, so I don’t think it’s meant to get around tiktok/social media censors.
There are quite a few message boards out there still, even outside of Reddit, Facebook, etc.. I can’t keep up with the ones I’ve joined. But no, I haven’t seen anything like “the pit” on any other forum, past or present. It’s hard to know if that’s a good or a bad thing. Probably both.
One of my favorites, Ravelry (for fiber artists) has done this over the years.
Before the 2008 election, an anti-Obama group was formed called “The Bunker” which got Ravelry on Secret Service’s radar, because people were there talking about how they planned to assassinate him (and apparently thought nobody else would see it because it was password protected), and I’m pretty sure some of them are still doing time for it! For a while, the word “bunker” was flagged, and a reference to the board would get a friendly notice from the staff to please edit that post. The board was archived off-site for a long time, and later restored for historical context, I guess.
In 2020, their staff also decided to disable the conservative-oriented political boards, for similar reasons. Once in a while, a troll will slip through, but they’re really easy to catch. It’s one of those “if you can’t play nice, don’t play here” things.
I found a teen-oriented board while noodling around online one time that had the usual rules about religion and politics, and added that kids could not discuss sports teams, rock bands, or sexual experiences, real or imagined. OK, they could say “I like the Cubs” but you couldn’t say “People who like the Cubs are idiots.” I mentioned this, on Ravelry no less, and another poster said, “So, what DID they talk about?” LOL
The closest thing to a Pit I found there was their Atheists and Agnostics board. Some of those (mostly) women are brutal.