Some people just tend to let go....if there's no chance of them being found out and possibly teased, some people will just act really perverted online, because they know that the other person doesn't know them in real life.
Or something like that. It made sense in my head!
Although once, I text my friend, but she'd changed her number without telling me. I got this guy instead, and he rang me asking who I was. I said it was a mistake, but he realised I was female, so he asked me out on a date! Stupid lech....he only asked because I was a girl.
So I just babbled about how I was 15, and hung up. God, that was embarrassing.