Don't playfully tease internet strangers as if they're your close friends. That shit's rude.

You can become close friends with people online. I've done it. I love my twitter friends dearly, and we gladly poke fun at each other and have a good time doing it. But follow social protocol. Become friends first, mutually, gradually. Don't just start with "your mom" jokes.

And don't confuse politeness for friendship. Not everyone you're familiar with online thinks of you as their close friend. Think about the social cues, not just your wishful thinking.

We've all seen people online whom we hope to befriend someday. Most of those friendships aren't going to happen. Even people with higher follower counts than you feel left out of most circles, and usually won't be getting in. That's society. That's life.

Studies indicate a person can realistically maintain about 250 active acquaintanceships at a time. (Shut up Windows, acquaintanceship is too a word.) Don't assume you're in someone else's 250 unless it's really obvious that you are. There are indicators. Think about them.