Hard question. Open to suggestions. Even if a post starts off with a click-bait-y title/source, our member typically post concrete sources and more resources in the comments. The discussions are a large part of the community and, as of now, we are not overrun with bad sources/posts. I inclined to create a plan, but not implement until we have more issues. I'd like to say the community decides, but it could lead to endless polls about sources. Thoughts?

Frequency of reports?

Absolutely would be one metric. So far, we get very, very, very few reports in the Space community. Mostly the reports are to remove trolls or unrelated content.

Moderator discretion?

It would probably start here. Not sure I'm comfortable making those decisions, but this is likely the reality until we have more discussions and decide on a path forward.

Community vote?

This would be pretty great...just not sure how to go about it. I guess we could sticky a vote post for a few weeks or something.

Could a source ever be removed from the list if its quality improves?

We would have to have a mechanism for this. Times change. So do journals/magazines/periodicals.

I believe that Otter is correct, there is no way to restrict domains on a community level. So this would be managed by the mods supported by reports from the community.