I play way too tight anyway so I get a chance to observe more before making a determination. I like to give the benefit of the doubt and respect on that until I start seeing 3-4 offsuit or something crazy being shoved by the new player in town. Even at that...what you see in one game from a freeroll player might be entirely different than the overall picture. Sometimes people are tired or disgusted. Have to leave the game or whatever else and are just playing crazy in that one instance. In the buy in games, you probably don't get much of that though.
I try to look at everyone the same. In the past there were players who played horrible at my tables and it cost me in the long run in future tounaments against them. Since it is online, I try to not look at the names of the players at the tables. I focus in my cards, the amount of players in the hand and my chips. I just try to play the best possible poker I can play. I think poker can be just as much a mind game as much as a game of skill.