Needed: Infrastructure to Make the Web Personal – GigaOM.
Think of this as asearch problem. Traditionally, there was an index of every document in which every word occurred. When a query was received the search engine could just look up the precomputed answer to which documents had which word. For a personalized search, an exponentially larger index is needed that includes not only factual data (words in a document, brand of cameras, etc.) but also taste and preference data (people who like this camera tend to live in cities, be under 40,love “Napoleon Dynamite,” etc.).
Unfortunately, personalizing along 100 taste dimensions leads to nearly as many permutations of recommendation rankings as there areatoms in the universe! Obviously there isn’t enough space to precompute what recommendations to show every possible type of person that queries a site.
Continues @http://gigaom.com