Thanks to Julian McAuley for sharing the Amazon data from his papers below:

Image-based recommendations on styles and substitutes
J. McAuley, C. Targett, J. Shi, A. van den Hengel
SIGIR, 2015

Inferring networks of substitutable and complementary products
J. McAuley, R. Pandey, J. Leskovec
Knowledge Discovery and Data Mining, 2015

Thanks to Kenneth Lim, who did most of the coding in Ruby, for the collaboration on SortMySkills. We had a great time building it together during our time at IBM.