Usability Views Article Details  home | timeline | recent | popular | e-reports | userati | books | about  United we find (19 Mar 2005) This increasingly pervasive technology looks for patterns in people's likes and dislikes, and uses those patterns to help people find things they did not know they were looking for. Computer scientists term this task, in a welcome respite from jargon, “find good things”. Collaborative filtering also has the power to do the converse, “keep bad things away”, for instance by filtering unsolicited commercial e-mail messages, or spam. Systems that use collaborative filters to keep spam away already exist, though there are many other ways to do the same thing. Finding unknown good things, however, can at present only be done using collaborative filtering. The idea has been around for over 15 years. Early prototypes at Xerox PARC, a corporate research facility in Palo Alto, California, date back to the early 1990s. But the delay between the genesis of the idea and its widespread implementation turned out to be quite long, for two reasons. First, a successful collaborative-filtering system is computationally demanding and becomes rapidly more so as the number of users increases. A prototype system might have a few thousand users, which is manageable, but a real-world system will have millions—and the difference in scale introduces new challenges, which have been only recently overcome. Article URL: http://www.economist.com/science/tq/displayStory.cfm?story_id=3714044 Read 66 more articles from Economist sorted by date, popularity, or title. Next Article: Andrew’s Usability in the Real World: Living with the Nintendo DS     This site is a labour of love built by Chris McEvoy