The more repetitive a topic gets, the more users flag it. 'Is down' posts are repetitive as a category to begin with, and 'X is down again' posts are repetitive along two axes. There was one of these a few hours ago, before it got flagged:

https://news.ycombinator.com/item?id=22955595

... which was likely because users regarded it as a quasidupe of

https://news.ycombinator.com/item?id=22935941.

By 'quasidupe' I mean it's not strictly the same story, but the difference ('down again') isn't significant enough for the thread to be substantially different.

(The submitted title on this one was "GitHub: Here We Go Again".)