They are not limiting the amount, retards, they are throttling the speed, so when you hit the high cap your speed is throttled back to like 56k. You still get unlimited data, it's just slow as shit after you hit the cap.
http://www.macrumors.com/2011/02/03/verizon-reserving-right-to-throttle-data-speeds-for-top-5-of-users/