I've been meaning to answer one of these for a while. Not sure why I picked this one, but... My response is yes, I believe so. Of course, there are certain factors that need to come into play. For example, both people need to be honest with each other. (You can't have a real close relationship if you're lying about everything, even if the other person doesn't know. It'd be a lie.) But... I have three very close friends that I talk to pretty much only online (and the occassional text). With these three, the amount of online relationship varies. One friend, Josi, I met at school and then we started talking online. She used to come over a lot, but now with school and various other things that have kept the both of us busy, our relationship is about 99% online. (Althought that may change as summer or school breaks come around.)
Another friend of mine, Savvy, I met online first. She lived (and still lives) about four and a half hours away. (I actually met her through Josi. :P) Josi and Savvy had known each other for a couple years and were very close. After I had known her for... a year or so? (that's a guess) she came to one of my birthday parties and met me and Josi. I, myself, didn't feel uncomfortable about it at all. (I sat on her and that quickly broke the ice. :D) Since then Savvy has come over and visited me and Josi about 5 or 6 times and it's been great everytime. She is both my and Josi's very close friend.
And then there's another person I know and met entirely randomly online, Brandon. He lives in Texas, whereas I am in California. I've talked to him on the phone, but have never met him face to face. Regardless, he is a very close friend of mine.
I think people can become very close friends online, but I wouldn't commit myself to someone I had only met online. I wouldn't get in a relationship past very close friends, in other words. I think it's important to spend time with someone in person before committing yourself to them. But I still believe that very close and wonderful relationships can come out of time spent online.
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