Hacker News Reader

The technical name for this is "collaborative filtering". I think they are basing their work on this paper

- http://www.jmlr.org/papers/volume10/takacs09a/takacs09a.pdf

EDIT: Actually looks like Eq (15) from

- http://public.research.att.com/~volinsky/netflix/BellKorICDM...

Anyway there are lots of papers around on the topic.

They do mention that in the 2nd paragraph and repeatedly throughout the article as CF. I found the article to be a nice primer on the topic as it listed common approaches to the problem.

Lots of research here, but the most interesting part is their distributed graph approach. Scaling up CF is a challenging problem, and the current open source implementations have problems at really large scales.

I hope they open source their Giraph implementation, or at least part of it.

Reply on news.ycombinator.com