The term collaborative filtering was first used by David Goldberg at Xerox PARC in 1992 in a paper called "Using collaborative filtering to weave an information tapestry." He designed a system called Tapestry that allowed people to annotate documents as either interesting or uninteresting and used this information to filter documents for other people.
There are now hundreds of web sites that employ some sort of collaborative filtering algorithm for movies, music, books, dating, shopping, other web sites, podcasts, articles, and even jokes.
Collaborative Filtering is used by recommendation engines
Share this highlighthttp://www.safaribooksonline.com/a/programming-collective-intelligence/20386/