[3] A number of software applications either explicitly or implicitly take attention economy into consideration in their user interface design, based on the realization that if it takes the user too long to locate something, they will find it through another application. This is done, for instance, by creating filters to make sure the first content a viewer sees is relevant, of interest, or with the approval of demographics.[4] An attention-based advertising scheme may say they are measuring the number of "eyeballs" by which their content is seen.[5]