I have forums (well one in particular) to thank for improving my confidence and comfort during face-to-face social encounters. I used to become extremely self-conscious and anxious in most social situations involving people I didn't know very well. After spending time on that forum forming comfortable relationships online, and having those relationships easily transition offline into equally comfortable, and eventually strong and close relationships, I gradually became more comfortable forming friendships with people who'd had no exposure to me offline.
The best part about forums for me has been earning the respect and admiration of others, and seeing that respect and admiration displayed as clearly online as offline. But then that's probably due to my choice of friends; I choose as my friends those who don't believe in pretending to be someone they're not. They behave online the same way they behave offline. I try to do the same but I usually end up talking a lot less in person
I still get self-conscious and anxious in some social encounters, including ones such as dinner with not-so-close-friends which inherently have no cause for anxiety, but it's not as troubling as it used to be, and often unnoticed by others.