One phone call to a country such as Pakistan might not in itself say much, but what if three of your own phone and email contacts had made one in the past year, and you also browsed through some quite radical websites protesting at the „war on terror“ last month? Or bought three philosophy and history books that have previously been found in the collections of terrorism suspects? Much more complex patterns are generally being sought out by data analysts, in the way that Google (for example) uses more than 200 different „signals“ about the quality of a web page to generate its search rankings.