According to this highly viral and popular tweet from democracy diva, Mark Zuckerberg created a website to rank his classmates by their appearance, however, I haven't found any evidence to substantiate that claims.
In a testimony to the US House Energy & Commerce Committee, Mark Zuckerberg confirmed that he created such a site, called Facemash, in 2003.
LONG: "You put up pictures of two women and decide which was the more attractive of the two, is that right?"
ZUCKERBERG: "Congressman, that is an accurate description of the prank website that I made when I was a sophomore in college."
However, he denies it was related to Facebook.