In pictures: Online gamers unmasked

"Mark is a graphic designer and in his spare time creates robot avatars for sale in Second Life. He makes steady side income of $200 a month.

It's a niche market. If he was producing clothing for female avatars he’d be making much more.

But he isn’t looking to make a living from it just yet. He believes that the skills he’s learning in the game will one day be very valuable as more and more of the internet becomes 3D." (Robbie Cooper)