Collaborative Filtering

• Collaborative Filtering is a standard data mining technique used for web sites.
• It's not particularly new (~1989), but is really commonly used.
• Here is a paper on Eigentaste: A Constant Time Collaborative Filtering Algorithm.
• The idea is that you want to use one user's preferences (e.g. internet clicks) to rank things for other users.
• One thing to note is that it uses proof to show it is O(1) (ok it doesn't show the proof, but ...) for lookup.
• Secondly, it shows simulations on data sets.
• Note it doesn't use clicks but user rankings.
• Solid methodology (proof and simulation), highly cited.