I believe it has affected me, and that the effects are positive.
Meeting people online taught me that there are people out there who can understand me, and who share my feelings and interests (I previously didn't have people like that in my life).
After spending time on the Internet, I became more willing to take chances with what I said to face-to-face friends, but so far it has panned out -- the few I have opened up to are much closer to me than they ever could have been otherwise.
If I ever open up to someone and they can't accept the "real" me, then I still won't consider it a mistake to have spoken my mind. I think it's probably better to know sooner rather than later whether you're compatible with someone. Prior to finding Internet community, I had some face-to-face "friendships" that went on for years without the other person ever really knowing anything about me beyond a surface level.
Being lonely in a crowd is no better than being lonely by oneself -- for me, it was worse. So, I'm very glad the Internet gave me the opportunity to learn that I can be fully myself and still be likable/lovable.
The acceptance I've gained from people on the Internet has given me the courage to seek that same level of intimacy with people in "real" life, and my life is much better for it.
A life of pretending is no life at all, on the Internet or anywhere else.