Disclaimer: I am one of the mods there.

The subreddit had some major issues. Some might remember what happened in the first season of Serial on r/serialpodcast. r/MaM was not much different: An unsolved case, a false conviction, people get hooked and start investigating. Unfortunately a side effect of all those investigations is that innocent people become the prime suspect of thousands of people at the slightest hint of some kind of involvement (read, "he looked funny when he gave that interview"). People would share home addresses, phone numbers, facebook profiles etc. Many of those were filtered through AutoModerator. We also where going through the mod queue, the comments etc, to keep everything in check, but we still couldn't really keep the subreddit under control. People like family members of Steven Avery (the main protagonist of the documentary) would be harassed. Some people went to Avery's home town and tried to force people into admitting that Avery was not guilty. It was straight up harassment.

We felt that the submissions and discussion in our subreddit were a major factor in getting people to do those things. And while they didn't happen on a daily basis, there was no way for us to tell which post would trigger such behavior. We had hoped that that kind of behavior would eventually stop and that by removing links to social media, and by removing dox, not too much harm could be done. But four months in, the subreddit was still full of speculation, post accusing individuals of "having done it" etc. And all in all the atmosphere was, to put it bluntly, toxic. People were being trolled (so called "guilters" would come in, just to provoke people), or were venting their anger at law enforcement or the prosecution in that case (which is fine as long as it doesn't lead to harassment/witchhunting, but it did). There was calm discussion but also a lot of anger and mob mentality. We were still a hub for harassment against people that are most likely innocent. The subreddit would frequently focus on one individual for about a week a look for reasons to hate them...

We decided to make a change.. Speculations and theories would be moved to an alternative subreddit (r/TheoryOfMaM). People could still investigate (and as many will point out, even Avery's former lawyers appreciate some of the findings by internet detectives), but it would be a much smaller community. In a small community people think for themselves, there is no hivemind mentality. You can't make the most insane claim and still find people who agree. In a small community, people don't get riled up as easily and start doing stupid things. There's no fun in trolling in a subreddit where a post gets a dozen comments at best. You won't feel the need to harass people irl to show off in a community of a few hundred people. Well, in theory at least.

Aside from that, the documentary makers never told people to focus on only that one case, let alone solve it. The message was more about how the US judicial system is broken, and how investigators can have tunnel vision and make bad decisions that can ruin a person's life. Discussion about any kind of false conviction case is welcome in our subreddit, but we wanted to draw a line when it comes to solving any of those cases. Most of the time, that is not a good idea and innocent people can be harmed.

The change didn't go over well. We expected that. But we knew were we wanted the subreddit to go. There was no point in making an announcement, suggesting changes or looking for compromises. Most of us have done those kinds of posts, and in a subreddit with such a controversial topic you never get any kind of clear decision. Many people have told us that the reasonable part of the community would have understood, that we should have given them a warning. I believe them. We did give them a warning, though. They just didn't like it.

Shortly after the announcement (maybe even on the same day) a new subreddit was founded: r/TickTockManitowoc. We had hoped that would be it, but there is still some animosity sadly. As you can see from the other comments.

FAQ

Why are you removing old posts?

I know of one series of old posts that were removed. They were removed after they were repeatedly edited in protest of the recent changes, when posts get edited, they land in our mod queue again, and are reviewed. When a post says "fuck the mods" it's off topic.

Why do you let mods call Avery's lawyer an ambulance chaser?

One mod did. It's not against our rules.

Why do you let mods call the subscribers [slur/stereotype/etc]?

As far as I know that didn't happen on our sub, so while I find it is in bad taste, (1) it wasn't unprovoked, (2) if it wasn't on our sub I can't do much about it. I've also told everyone not to engage people when they start accusing us.