Nielsen//NetRatings measures Internet and digital media audiences through a telephone and Internet survey. Nielsen BuzzMetrics measures consumer-generated media. Other companies collecting information on internet usage include comScore, Wakoopa, and Hitwise, who measure hits on internet pages. Companies like Visible Measures focus on measuring specific types of media; in the case of Visible Measures, they measure online video consumption and distribution across all video advertising and content. GfK offers Cross Media Measurement Solutions that allows to attribute offline sales to media exposure across TV, Internet and Mobile utilizing its proprietary LEOtrace technology.