Long story told in short:
I am a great fan of Star Wars and the space simulator games written for it. In X-wing vs TIE Fighter and X-win Alliance, it was said it's impossible to reach the ranking of Top Ace in Single Player, but after months of playing dogfights and missions, I managed to achieve it. I initially wanted to be simply "Ace" when I was to create a login name for myself at HLP, it was taken already. So I stuck the "Top" in front of it and ended up as "TopAce", no spacing between the two otherwise separated words and I kept double capitals.
I've been calling myself as "TopAce" on the Internet ever since. I used to be "Brazil" or simply "Bra" (as a three-letter abbreviation for Brazil), but after two years of learning English, I realized it had an other sense, so I changed it.