I don't think we've had a thread on this topic so I'll start one to see if it gets and takers. First item for discussion is Uli Hesse's interesting column over on Soccernet about whether you should position defenders on the posts for corner kicks. He points to several examples where this creates a mismatch for the corner taking team since the player on the post cannot mark an attacker. Interesting in that probably 99% of the time, the posts are guarded. It also makes the offside trap more difficult once the ball is initially cleared (assuming one has a keeper that can punch the ball away).