Internet friends?

Is it possible to be friends with someone you know only on-line? How much has to be known about someone (and they about you) in order for you to be friends?
It is my belief from personal experience that such a feat is probable and possible. I own a Playstation 3 and have an online ID that I use every time I play. Therefore I meet new players in every game I play. However, if you join a "clan", the term used in the online gaming realm meaning "team", you have to be able to give up some sort of information to the other members such as your time zone, name, and favorite color (hahahaha that part is a joke). Anyways, going back to online friends, this past year I decided to make a clan of my own for a game called Warhawk which has become the largest PS3 multiplayer game with over 400,000 players worldwide all involved in over 1000 major clans. Well, I hoped on the bandwagon, and opened an online recruitment room where I gauged the talent of various players. After 3 hours of wasted time yielding only one possible prospect, I was about to turn off my PS3 when I saw that three players (SuperJam79, Grizzla90, and IngaNarf) on my Friend’s List who I had sent messages back and forth casually were playing Warhawk too. I sent them messages asking if they would be interested in joining my clan. About a week later I received replies from all of them saying that they were interested. I arranged a chatroom and they joined. It was quite an interesting experience to say the least not knowing what to expect at all. It turned out that they were all my age, so it made it easy to figure out when we had tests so we couldn’t schedule battles on those nights. We got a rigorous and ambitious battle schedule set up, and started practicing. Well, after about three months we had a 1-1-10 record, and so we said we’d take a break for awhile work on our skills. However, we were on first name basis by then, so myself, Chris, Jamar, and Tristan all knew each other pretty well just from playing video games. For about 2 hours a day. As crazy and as anti-social as it sounds, I looked forward to talking with them every day. On the weekends, I would help Jamar with Spanish in a chatroom, Tristan and I would swap the latest gaming news, and Chris and I, being the oldest, would talk about literally everything, nothing was off limits. Sometimes his girlfriend would get on with us and we’d just chill out on Saturday nights when nothing was going on. Eventually, we added each other on Facebook, so now we can stay in touch at anytime. From what Chris had described, he lives fairly close to Shields, and since my high school choir toured NYC this year, Tristan came to one of our concerts. I think that overall, you have to be careful online, but I personally don’t have any problems with having online-only friends.