With this in mind, the conclusion of the blog post is hilarious. Quotes from the blog post: > [The] rough idea is that if, say, Alice spoke to Bob for a long

With this in mind, the conclusion of the blog post is hilarious. Quotes from the blog post: > [The] rough idea is that if, say, Alice spoke to Bob for a long time and then Alice also spoke to Carol for a long time, then Bob and Carol are more likely than not to speak for a long time too. > [...] > The data have clearly shown us that, despite proving a successful technique for many other products across a range of contexts, collaborative filtering simply wasn’t a match for Chatroulette. Basically: 1) make an arbitrary assumption about your data, 2) apply a widely-used recommendation algorithm, 3) notice that the results are really bad, 4) reject the algorithm... rather than the assumption. Admittedly, I don't know whether the algorithm requires this assumption, or whether a slightly different one could be used. For instance, if Alice spoke to Bob and Charlie, then Bob and Charlie don't want to talk together. Or, if Alice spoke to Bob and Charlie, and Carol spoke to Bob, then Carol should be recommended to Charlie, etc.