Not all ad impressions are created equal. That, in essence, is the key takeaway from new research scheduled for release today by Casale Media. Above-the-fold ad placements displayed within the first screen of a user's browser window were found to be the most effective. In fact, they are almost seven times more effective at generating a click-through than ads delivered below the fold. Based on analysis of nearly 2 billion ad impressions in the first quarter of the year, Casale also found that users were three to four time more likely to act on an ad if it was the first or second one they saw during their session. From there, ad effectiveness plummeted as the user progressed through their online viewing. Casale also noted that repetition does work -- to an extent. For example, ads shown five times or more to a user were 12 to 14 times more effective than ads shown less than five times. However, marketers needed to apply frequency capping to prevent over-saturation. "Relying on singular indicators, such as reach or hyper-targeting, does not tell you the full story," Joe Casale, CEO of Casale Media, said of common ad placement practices. "Vigilance on the part of marketing managers and accountability from their advertising partners are vital to executing a successful campaign." Furthermore, Casale's findings indicated that advertisers -- and particularly those focused on brand penetration with consumers -- should take into account a number of factors when considering the environments in which their ads will be running. Campaigns often suffocate from reduced share of voice on cluttered Web pages. They are ignored when surrounded by engaging content like photo galleries. They may not even be seen by their audience when displayed on a Web site that inflates impressions through auto-refresh mechanisms. All impressions sampled during the research period went to performance-based campaigns running Flash-based creative. All creative clicked through to simple, one-step actions like newsletter sign-ups.