Hi. I don't take notes, but I think it would be helpful. Previously, when I often played online poker, I used Hold'em Manager and I had enough statistics on the players that he collected for me. I think if you use software such as Hold'em Manager or Poker Tracker, then there is no need to take notes. At PokerStars, you can mark players with different colors in order to know which of them plays aggressively, who plays passively and who plays loose.