Implicit data and collaborative filtering

A lot of people these days know about collaborative filtering. It’s that Netflix Prize thing, right? People rate things 1-5 stars and then you have to predict missing ratings.

While there’s no doubt that the Netflix Prize was successful, I think it created an illusion that all recommender systems care about explicit 1-5 ratings and RMSE as the objective. Some people even distrust me when I talk about the approach we take at Spotify.

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Vote for our SXSW panel!

If you have a few minutes, you should check out mine and Chris Johnson‘s panel proposal. Go here and vote: http://panelpicker.sxsw.com/vote/24504

Algorithmic Music Discovery at Spotify

****Spotify crunches hundreds of billions of streams to analyze user’s music taste and provide music recommendations for its users. We will discuss how the algorithms work, how they fit in within the products, what the problems are and where we think music discovery is going. The talk will be quite technical with a focus on the concepts and methods, mainly how we use large scale machine learning, but we will also some aspects of music discovery from a user perspective that greatly influenced the design decisions.

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What's up with music recommendations?

I just answered a Quora question about what, if any, are the differences in the algorithms that are behind recommendations for music and movies.

Of course, every media type is different. For instance, there’s fundamental reasons why latent factor models works really well for music and movies, as opposed to location recommendations where I suspect graph based models are more powerful. People recommendations is another animal and I’m sure beer recommendations has its own domain-specific quirks.

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3D

Andy Sloane decided to call my 2D visualization and raise it to 3D.

(Looks a little weird in the iframe but check out the link). It’s based on a LDA model with 200 topics, so the artists tend to stick to clusters where each cluster is a topic. The embedding also uses t-SNE but in three dimensions (obviously).

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2D embedding of 5k artists = WIN

I’m at KDD in Chicago for a few days. We have a Spotify booth tomorrow, and I wanted to put together some cool graphics to show. I’ve been thinking about doing a 2D embedding of the top artists forever since I read about t-SNE and other papers so this was a perfect opportunity to spend some time on it.

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