To put it in a sentence, all five of yesterday's winners drew while one of yesterday's "drawers" won. Thus Nakamura, Kamsky, Akobian, Lenderman and Onischuk (the last two with each other) all drew while Kaidanov won, and so all six lead the 2012 U.S. Championship with 1.5 points. Hess and Shulman have a point apiece, Ramirez and Robson each have half a point, and Seirawan and Stripunsky have castled kingside (0-0).
Ramirez - Nakamura was a Fianchetto Gruenfeld that wound up drawn. Nakamura outplayed Ramirez and won the exchange, but with a somewhat exposed king he had to be accurate to convert it into a win. The crucial moment came when he played 35...Kf7?; 35...Kh7! 36.Bxh6 Qf3 37.Be3 f4!! was the path to victory. In the final position Ramirez could have played for a win, but decided to call it a day.
Robson - Kamsky saw the latter choose the unusual 1.e4 c5 2.Nf3 b6. I don't know if Kamsky believes in this or felt it was good for a one-time try, but it worked. Indeed, he seems to have acquired an advantage, but 22...Qxb4 more or less allowed a forced draw. 22...Nxe4 is an attempt for more, when White must try either 23.Ba3 or 23.Qh6 to stay afloat.
Onischuk - Lenderman was a "correct" draw in a Ragozin system. White had a very small pull for a long time, but Black gradually managed to neutralize the pressure and hold the game.
Akobian - Kaidanov was another instance of the correct draw genre, a sort of Chebanenko Slav where Black temporarily sacrificed a pawn, only to win it back a few moves later and reach a dead drawn ending.
Kaidanov - Stripunsky was a sort of Catalan/Semi-Slav hybrid. White gambitted a pawn for long-term pressure, and it paid off when Black played 24...Be6 rather than 24...Rb6. Black was soon forced to give up his queen, as 27...Nd7 28.Ne7+ Kh8 29.Rd4 (threatening the stock mating combination 30.Qxh7+ Kxh7 31.Rh4#) 29...h6 30.Bxd7 Bxd7 31.Qd2 wins a piece while maintaining an overwhelming position. In the game, Stripunsky's 27...Qxd1+ 28.Qxd1 Bxf5 29.Qd4 Rd8 30.Qxa7 gave White a queen for a rook and knight, which wasn't enough. He put up a lot of resistance, but Kaidanov never let him off the hook, and converted in 53 moves.
Finally, Seirawan - Hess was a 4.Qc2 Nimzo-Indian where Seirawan pushed and pushed and finally overpressed. 27.Ng3, keeping Black's queen out, would have given him an edge, while Qd1 on move 28 or 30 would have kept approximate equality. Perhaps Seirawan missed Hess's 31...Rb3, after which White was down a pawn for nothing. Soon it was two pawns, and Hess converted it into a full point without difficulty.
Round 3 Pairings:
Shulman (1) - Seirawan (0)
Stripunsky (0) - Akobian (1.5)
Lenderman (1.5) - Kaidanov (1.5)
Kamsky (1.5) - Onischuk (1.5)
Nakamura (1.5) - Robson (.5)
Hess (1) - Ramirez (.5)
Ramirez - Nakamura, with some notes, can be replayed here.