Used with the .Colors image method, this will return a random, dominant color from the image. Unlike the shuffle function, this will return the same color on a given page every time you build the site, because the “random-ness” is based on the page title. Change the page title, and the color may be different.
So, what I like about the above approach is that it will give the same color for the same string, useful if you want to put some colours to your taxonomy terms etc.