Abstract: A computer-implementable method for determining an advertisement position is provided. The method includes receiving, at a server, a user request, via a computer client, for displaying a webpage in a window of a browser of the client computer, where the webpage includes at least one ad. Further, the method includes receiving viewport information from the browser. Based on the viewport information, viewable canvas information is calculated. The viewable canvas information is related to a displayable portion of the webpage. The method further includes generating ad position information based on the viewable canvas information. In embodiments, the ad position information is for determining fees related to advertising on the webpage.