Cost-per-engagement (CPE)

With cost-per-engagement (CPE) bidding, advertisers only pay when users actively engage with ads. For example, advertisers pay for lightbox ads (a type of expandable ad that can expand to a very large size) on a CPE basis, which means that publishers generate earnings from lightbox ads when users choose to engage with the ads, e.g., by hovering over them for two seconds to expand the ads.