Question visibility and reputation I wonder whether the visibility of a post changes according to the user's reputation asking the question. Is it also known if a user's posts' visibility is affected by other actions, like having _mistakenly_ flagged a question, an answer, or a comment as inappropriate?

It depends on where you're looking, but in general, the visibility is **only** determined by the timestamp (either of the last activity, or of the moment the question was created). However, on the homepage, questions with a score of -4 and lower are hidden. In any case, reputation doesn't matter; Stack Exchange is all about the content, not the person who wrote it.

Your flags don't have anything to do with whether your questions are visible or not. (With a reputation of 11, you can't even flag anything except your own posts, FWIW.)