Many posts are being categorized by the posters inappropriately. I suspect they figure they will get more exposure by cross posting, but when I click on Education I am not interested in wading through posts on everything.

The best would be if every item starts off cross posted and then drops out of categories in which most users negate that category. Posters would not have to do the extra step and people like me who are motivated to eliminate the inappropriate items would do the work.