I think slashdot intentionally(?) picked silly voting reasons. Spam, Mean/Abusive/Rude, Incorrect would cover the vast majority of reasonable downvotes, I thin

I think slashdot intentionally(?) picked silly voting reasons. Spam, Mean/Abusive/Rude, Incorrect would cover the vast majority of reasonable downvotes, I think, and are fairly distinct and intuitive. There are some gray areas about downvoting (something which is interesting but offtopic: is that spam?), but I don't think those gray areas usually are between two of these categories.