I was going to post a comment to Valerie's online relationship post, but then I realized I just had way too much to say on the subject in the form of useless background information and other kinds of silly babbling to squish it all into a comment.
I'm definitely coming from the perspective of "TheNewerVal" in Valerie's sample conversations. I learned to socialize online, and gained a lot of self-confidence through my online friendships. I also made some bad choices with people online. They weren't any worse than bad choices others have made in meeting people in meatspace. But those bad experiences also give me a perverse little bit of cynicism about online relationships. I don't see them as a replacement for "real life" friends, but I do see them as a great way to meet new people and augment my current social life.
I don't think I ever suffered from a disorder that kept me from socializing-- my problem wasn't chemical. When you grow up on a sail boat and then move around a whole bunch before age eight, when you're a pretty intelligent kid with a weird imagination and more skill at talking to adults than people your own age, it's kind of hard to make friends with your peers. I was skinny, precocious, outspoken, I dressed funny, and I didn't let other people's opinions make me change who I was. But I still wanted to be liked for who I was, and that led to a lot of emotional suffering during most of my formative years.
Flash forward to 1996. It's my senior year of high school, I've already been playing around with that BBS stuff, downloading games. My friend Jeff and I have been mailing floppy disks back and forth containing bootleg games and little programs written in BASIC. My family has just started dialing into an ISP and downloading web pages from the WWW at something like a 9600 baud rate. Then, a classmate of mine says to me, "You should get AOL! It's great! You can chat with people in real time!" and I begged with my parents and we signed up for what turned out to be overpriced per minute charges at slow speeds and constant busy signals with access numbers. But in the midst of all that, I started hanging out with a bunch of people who did online roleplaying.
I know what you might be thinking. Online friends and roleplaying? How much further can you sink yourself into the Kingdom of Loservania? For me it was a big step up. The roleplaying was good for the creative writer in me. It allowed me to put myself inside another personality, to play with traits and impulses in me that had been subsumed by shyness and isolation. Unlike the opinions of idiots like these (warning, scary site ahead, which can be thoroughly debunked by this site), roleplaying can be a pretty healthy activity. And for the record, I've never participated in murder-suicides or been possessed by any demons, to my knowledge.
During that time, I made some really good friends, one of which became one of the closest friends I've probably ever had. Those friendships gave me the confidence to start interacting more with folks IRL. It clued me in that I could be a relatively likeable person when I wasn't trying too hard, and it got me used to dealing with and relating to people from all different kinds of backgrounds (believe it or not, 14 year olds are not the only people who roleplay-- two of the people who ran a particular game were a married couple with a son in high school).
I won't say that my online friendships (and subsequent romantic relationships) were the solution to my shyness. But they gave me a relatively pressure-free training ground to work some serious stuff out. If things got too dicey for me, I could always log off and write an email after I calmed down. And there's also something about online interaction that encourages a kind of honesty and intimacy that's hard to reproduce in the real world. Those kind of experiences later lent depth to my real world friendships.
Yes, there are people who lie online (and not all of them are marketing jerks creating blinking banner ads). I've had some scary experiences with that. A college friend got involved with a guy she'd met online over spring break and decided she was going to marry him after a week. She went to visit him and ended up being pushed into having sex against her will. Did this happen only because it was an online romance? No, of course not, take out the "she met him online" part and you have a pretty typical story about a girl with low self-esteem who just wanted somebody to love her and threw her common sense out the window. I've had experiences of my own that were fairly similar (though, fortunately, didn't result in rape). In retrospect, you can spot an online liar pretty much as easily as you can spot a liar face-to-face. All you need is a good lack of naiveté and a wariness when someone is telling you exactly what you want to hear.
After a lot of experience, I developed a few personal rules for my online interactions. I don't expect these to be universal rules, but they've worked well so far for me. One is that I hardly ever turn away anyone who wants to chat with me (one of the few exceptions is people who are obviously trying way to hard to get into cybersex-- those, I just mess with their heads. I've met some really interesting people from random ICQ messages.
My second rule is that if I'm going to meet someone from online in person, I need to have an escape route or a backup plan, in case things go incredibly awry one way or another. It doesn't even necessarily have to mean that the person is questionably trustworthy; it's a good general long-distance-travel rule as well. My final rule is that if things take a romantic turn, I definitely meet that person as soon as I possibly can. With that kind of relationship, nothing replaces the gut feeling you get when you see the other person eye to eye. My first "boyfriend" was a guy who lived on the other side of the country that I never met for two years. That ended up in a miserable mess that I won't get into because this damn post is already too long. My current boyfriend is one I met online as well. We met in person a few months after we decided we were interested, and when I first saw him at Heathrow airport, sparks flew, and they've been sparkling since.