here's a good opinion, i found in a forum...
Why Manny won:
In a 10-point system, the boxer* who wins a round is given 10 points, and the other * boxer gets nine points. (10 -9)
If there was a * knockdown in the round (10-

2 knock downs (10-7)
If a* judge can't decide who won the round, it is* scored 10-10.
Now if u are the challenger, u must be* the aggressor (Pacquiao vs Cotto) in very close* rounds the* Champion gets the 10. For example if* Pacquiao would just stay still and Marquez does not* attack, Pacquiao gets the 10 and Marquez 9. In this* case Manny(champion) was always aggressive while* Marquez(challenger) waits for an attack and* counters.
Marquez's body language fooled a lot of* people. Making people feel that he was the winner or* at least it was a draw. It may look like he was* landing more punches but the tricky part here is he* was on the defensive, luring pacquiao into his * tactical traps (remember the challenger must be the one* who is aggressive to be awarded 10 ). So even if * Marquez did connect more punches he gets only 9 for * being defensive and Manny gets the 10 for being the * attacker.
Pacquiao got more "10"s than * Marquez. Manny wins.
the Pacman will* still win if Marquez gets another shot (4th