There is a story I like to tell about recommender systems… Someone on the YouTube team once told me that they ran an experimental recommender to decide which frame of a video should be used as a thumbnail. The goal being to maximize clicks. After letting that recommender learn from user’s behaviors, it converged to… Porn! Ok, not quite porn, but the recommender learned that the more skin was visible in a thumbnail the higher the likelihood of a click. Naturally the experiment was scrapped (thank God for human oversight), but it still goes to show that purely metric-driven recommender systems can land you in a very weird place…
That’s what I feel is happening with Amazon’s recommender system picking the ads to run on my Facebook stream. The top picks systematically look like sex toys or, as is the case in the example below, drugs. They are all excellent at triggering my curiosity — and I’m sure their metrics show a very high click-through rate in average user’s — but they are pretty bad at convincing me Amazon is a great company…
Phil Beaudoin 