Long story short, pushing an inbox notification for a post here on MSE has brought in a lot of folks who don't normally visit this site. Which is good... Except that a whole lot of people don't realize they aren't on Stack Overflow anymore.
This is mildly annoying for us (employees) to deal with, and of course a terrible experience for folks who might otherwise be learning something about how this network of sites is governed. So last night, in hope of reducing some stress, I raised the reputation required to post from the default 1 to 2...
...Which had zero effect on anything because that setting has never been changed for anything but child meta sites before, and the code made a few crucial assumptions along those lines.
So a little bit ago, Nick decided to actually make it work by removing one of those (no-longer-correct) assumptions. Which worked! Hooray!
...but then put us face-first into another set of assumptions which involved dereferencing pointers to a parent site that simply doesn't exist here on good ol' Exceptional Meta.
This too is now fixed. For the next day or so, we'll keep the reputation required to post here at 2, thus requiring anyone wishing to participate here to have earned some reputation first (via edits or previous posts) or at least have earned the association bonus somewhere on the network. That oughta allow those of you who are new to the site to poke around and learn about what we do here without suffering the humiliation of mistaking it for Stack Overflow and posting your programming questions only to see them downvoted and unceremoniously deleted.
Once this... Unplanned mass initiation... Has passed, we'll drop the privilege back to its former value and go back to business as usual. And maybe think of a slightly more clever solution next time we need to push a post into everyone's inbox.