I just greet them as I would in real life if I know what who it is. I have different greetings for different people. If I dont know who it is I'll say "hello?"

I was going to make a thread about mobile phones but I'll just tack on a question in this thread

For those of you with touch screen moblies, do you push the phone all the way up against your face? I see people do it on tv and it seems weird to me. I always keep the screen away from my face though I'll angle it so the speaker is up against my hear if I cant hear them.