Holy s*** Desi Davila second overall in 2:22:38! That's almost a four minute PR from her time in Chicago last year, and is the third best time run by an American woman. Deena Kastor has the AR of 2:19:36 from London '06, and Joan Benoit Samuelson ran 2:21:21 at Chicago '85.
Geoffrey Mutai in 2:01:02 for the course record! Would be a World Record time, but I don't believe it counts since Boston is point to point. Current WR is 2:03:59 by Haile Gebreselassi at Germany '08.
Ryan Hall first American in 2:04:58! I'm not sure whether this counts as the American Record. I know it gets an "a" next to it on the bests list, but that's it. Previous (current?) AR was 2:05:38 by Khalid Khannouchi in London '02.
Boston is historically not a fast course, since despite having a net downhill, it's not flat, and it's generally accepted to be much slower than traditional World Record courses, like London, Chicago, and Berlin. Tailwind assisted this year, but fantastic day for running nevertheless.