Regular Banner ad units are served as popup or popunders for in this case, serving banners as pop ads allow more of user interaction and is best fit for Branding solutions and marketing approach. We support all generic ad units for this based on the campaign to campaign marketing requirements. Banner popups or popunders works well with promotional campaigns like those for shopping stuff, mp3 download stuff etc, since they are more of push marketing approach they focus on branding and reaching our targeted audience for brand promotion. Also if targeted well with keyword selection they do good enough to meet advertisers cpa goals.