As a viewer views and scrolls down a web content page in a browser window of a web browser, a predetermined ad placement area of the web content page scrolls into and out of a viewport of the browser window before it can be populated with rendered ad content. Upon detection of this condition, the ad placement area is moved to a fixed position in the viewport and ad content is rendered therein. The ad content remains in this fixed ad placement area for a predetermined time period, thereby lingering in the viewport despite any scrolling of the web content page.