I had a similar experience with IRC and Usenet - discovering people of different ages from all walks of life chatting about things that interested me, and learning about who I was outside the expectations of my parents and teachers. In a way, although I was born in the real world, I grew up on the Internet.
Rather than 4chan-style anonymity, where nobody can be identified or distinguished, I think pseudonymity is important for people discovering themselves—giving (good faith) actors the ability to build a reputation and have something to worth defending, encouraging them to continue to act in good faith.