Sounds like Fight Club syndrome to me.

Yeah I'm like that too but I really like it. It's part of the reason I like forums, I feel like I can be someone else who is superior. I like that I don't have to think so fast, I get to take my time with what I post so I can say exactly what I want to say. I usually jumble my words in most of my daily conversations. I like that I'm not nervous or shy about expressing myself. I like that I have an alias on this website and I like that I have a lot of control over what I share and don't share. I like that you're all beautiful strangers and that I am a stranger to you.

In short, I truly feel that I am a better person on this forum, I wouldn't say I'm pretending. I am being who I want to be and that is very therapeutic for someone like me who is used to dealing with a pretty low self esteem and very little confidence.