I don't think people really grasp how close people get to online friends; guildmates, clans, alliances.
I always thought it was a bunch of bullshit how people would not go out with real life friends when they had to raid, but after 6 months of it, I really do understand it.
People argue and say that you can't get to know people truly without face to face interaction, and to some extent, I guess that's true. But, the fact remains: after staying up to 4am with a group of people working towards a common goal, failing, and trying again, you get to know them pretty well. While I may not know all their eye colours, or even how they look, many aspects of their personality become apparent. After 6 hours of wiping on the Lich King, you learn things about people.
Some people think it's ridiculous that I'd consider some of my online friends to be some of my best friends, and I guess in a sense it is ridiculous. For all I know, they could be lying to me about everything. But online, people are the people they want to be. Things that would normally stop them from socializing with some people - appearance, age, occupation - don't matter. And the truth is, in my 5 hour Skype conversations, we've all shared some stuff we'd never dare to share in a face to face conversation.
I'm not saying that online friends are better than real life friends; real life friends are very good, if not better in many aspects. But still, I really wish people would judge less when I mention my online friends. It's a different type of friendship than I have with my real life friends, but that does not make it inferior in any way.