If someone types with "u" "r" "2" etc then I tend to think they are a stupid teenager who is too lazy to take an extra second and hit the two letters in "to". I tend to lose respect more so if they are an adult and are still typing like that.

I tend to think of a person I meet online as older. I'm always off by a year or so. It's not too much but instead of 22, I think they are 23! I always forget that Jiro is younger than I am. Some EoFFers have surprised me though. Like as mentioned RE and kentarou. Even Zeldy, when I first met her way back when I thought she was older than me.