My current vague hypothesis is that young people (a vague age group would be people between 16 and 30ish, since I can't interview anyone under 16) are more likely to make new friends via the internet, whilst older generations use it more to sustain existing, real life friendships.
A couple of years ago, I would have agreed with this statement.
As a younger person with not many meatlife friends, I spent much of my time on the Internet scouting out new people to pay attention to me. I've made some brilliant friends from that, some of whom I have actually met in real life. My first Internet meetup was with a guy from the Anti-Rice forums, and though we had absolutely nothing in common and hadn't even held a proper conversation over IM, we met up when he came to NSW because we were the only currently active Aussies on the forum. I drove for three hours to get to where he was and I didn't know the guy from a bar of soap. We actually had a really fun day hanging out in his Dad's pool and getting kebabs at the shopping centre, and for years afterwards, even after he left the forums we would text message each other with our latest news.
This positive experience made me sort of search out other Internet people to meet up with. I was overjoyed when I came to this forum and found so many Australian members, one of whom actually lived within a two minute drive of me! Everyone knows that Eris (Hannah) and Princy/Jmrz (Jamie) and I meet up relatively often and are good friends, and the meet-ups we've had with the QC Sydney crew and assorted interstate and international hangers-on have all been brilliant. I am sure we will all remain friends for a long time!
Lately I've started new relationships with photographers I met via Flickr and OzModel. All of them have been smashing to meet, and with the one big thing in common (that we all carry cameras around like a lifeline) we all have so much to talk about. The sharing of skills is a big thing when you all have a shared hobby, and there is already so much that they have taught me whilst fiddling with our cameras at the beach or at cafes.
Of course then there are the friends on Gabbly and IM, most of whom I have no chance of ever meeting. Plenty of you have made my life so much happier, and I am so glad to be a part of your lives! (Awwww.)
HOWEVER, I was supposed to be disputing that statement.
Lately, with the rise of Facebook et al, I have found myself using the Internet more and more to keep track of my meatlife, "Not Met Over The Internet" friends (I never was one for chatting to 'real' friends over IM, it felt slightly silly to me). My own little group organise all of our outings via Facebook messages, even if most of them see each other every day at Uni. Some of them religiously check my Flickr project, which is nice if a little disconcerting, because I'm, well, a lot more bold and vivacious on there than I tend to be around them, and some of my pictures make the more polite of them a little uncomfortable.
The only other people I know who use the Internet are my Dad and Grandfather.
My Dad (who is in his mid forties) uses it to make new contacts in the car racing world, meets up with his forum friends, buys things off them and trades hints. I am pretty sure he met his girlfriend over the Internet, and when he was in the market for a lady he would IM with local people (my brother would end up being embarrassed when it turned out that Dad was chatting up the mothers of girls in his class) and occasionally meet up with them. I do not think he has ever looked up any of his old friends, because he has the old tried-and-true mediums (turn up at their place to borrow something) for that.
My Grandfather (now in his seventies), who moved here from England as a young man, is an absolute computer whiz after being introduced to them about five years ago. He teaches "How to use the Internet" classes at his local community college, and religiously emails both his old friends from the UK and the new friends he has made through his computer classes, but as far as I know hasn't scoped out any new people to talk to, aside from sending the odd email to website creators to tell them what a good job they did on the site.
I guess what all that waffle was about is that people of all ages utilise the Internet to make new relationships and you can't put people in boxes blah blah blah and I never understood what Sociology was supposed to do anyway!
I just like to talk about myself.