What are your top ten favorite movies of all time? This is a very difficult question. But why? Irmak Sirer explains the challenges of measuring how much we like movies, books, songs, or products; combining insights from diverse sources like the Netflix Prize, Duncan Watts' social experiments, or the beginnings of Facebook. The better we get at measuring and ranking levels of enjoyment, the better we can customize websites, sort search results, find other people with similar tastes, and recommend products, so can we overcome these challenges? Drumroll... Yes, we can.