The 10-stroke rule no longer applies at the U.S. Open, beginning with the 2012 tournament. Only the Top 60 and ties advance to play the weekend. No golfer has ever made the cut through the 10-stroke rule and then gone on to win the U.S. Open, but the change will, most years, mean that about a dozen or so golfers who would have made the cut under the old rule no longer will.
Reason for the change? Keeping the field smaller for the final two rounds, ensuring 2-player pairings and (in theory, anyway) improving pace of play over the final 36 holes.
Tournament and tour cut rules