Apparently, the web is grey. After averaging the colours of 3000 or more sites using the temporary url2png service, the output colour is #9c9c9c; a pretty bog-standard grey.
It’s not really that surprising. The majority of the web uses black text on a white background, with the various other colours pulling the colour average up towards the black end of the scale (the red, green and blue averaging out to a grey).
Still, an odd piece of trivia that we’re bound to remember.