I have not made friends here, and I don't expect to. Not that people here aren't friendly - indeed, HN is the most civilized discussion group I've seen. Rather, I just don't enjoy making friends for the sake of making friends, and don't go out of my way to add people to my real-world social circle.
I have made one "friend" from the old Joel on Software discussion board. He's a guy who I convinced to take a shot at grad school in computer science after a bachelor's in Chinese didn't take him where he wanted to go. Unfortunately, he lives in LA and I live in Denver, so we haven't met yet - but I would consider him worth meeting in person.
It's really that simple. The circumstances, places and methods of communication are entirely irrelevant.