Awesome work, I really enjoy reading your experience on this. For the TFIDF approach, did you use clicks or purchases? I am also curious as to why you think the TFIDF approach is better in your case. I saw the imgur image that you uploaded, let's say I'm buying something for a party, isn't the buys/clicks recommendation better in that case? It'll show me all the items I may need for the party. Why would I want to see other similar items to what I'm viewing in that case?