Defenders move toward puck-handlers and force them to move the puck. This tactic forces the attacking player to decide between having his shot blocked or perhaps shooting the puck wide.
Teams like to cycle with two or three forwards circling in either the corners or around the net.
It allows shots from the point, but very little else. Remember that the home team has the advantage with the last change before every faceoff. The area between the two bluelines. Coaches tell their defenders this all the time. It means hitting an offensive player into the boards and pinning him there until the puck is picked up by one of the defender's teammates.