SevenCubed - 8:11 pm on Nov 5, 2013 (gmt 0)
It's not that THEY have the technology. There are a few websites out there in the wild that permit inputting a webpage URL and it will immediately return the average colour of the collective of colours contained within the page. THEY, once again, probably just adopted the technology that someone else created.
But as for applying it in the manner that IanTurner is indicating is kinda nifty.