Just to throw my 'history' into the fracas -
I've gone by many names online, this one being the longest lived and most generally accepted. (It actually sounds like a real name you know)
Anywayyyy this particular name comes from a novel by Ayn Rand -
Atlas Shrugged - The character's name was Dagny Taggart, and well, after reading the book a few times ( I think i'm working on 10 times) I realized I identified with the character. A minor spelling tweak so folks could pronounce it, and I was off and running.
Not so hard, now is it
Dagney