Until a few years ago MathOverflow front page had a short section at the top describing what the site is for. I am not sure when it disappeared or why but I would like to see it restored. Currently new users have no idea what kind of questions are appropriate here. One has to dig through Help center to find this info. This is not user friendly and most people would not know to look there. Adding a short "About MathOverflow" section to the front page should cut down on off-topic questions (calculus homework etc).