I play on about 3 different sites. I play on FTP the most and run into the same players over and over again. I started to notice this after I started taking notes on players. Not only do I see them in cash games, but also in tournaments. I've used notes multiple times to help me make either a call or a fold. The times I've called, I've come out ahead in the hand. Sometimes on the fold, I've was ahead, but I added to the notes. If you play the same limit for any period of time on any one site, you will start to run into players over and over again.

On the time aspect. I try to start taking the notes during the hand while watching. I will open the notes screen and start to type what amount they called and will type with "??" until I know. Then I go back and edit the notes to include the final information. I also use the hand history option, which gives a written history of the hand to make notes on hands. This allows me to fold a hand and make a note or two on a player. It's something you will get quick at with practice.