There's a misperception that display metrics only measure direct response. Brand advertisers rely on impression tracking and brand survey services like Vizu and Bazaarvoice, which are excellent for measuring memorability. Yet I'd argue there's untapped brand insight from display. It's understandable that brand advertisers aren't concerned with clicks or individual conversions, but they do want to know if ads engage consumers.
As experts and commentators make projections about how engagement should be defined and, more importantly, measured in display, it's becoming an industry consensus that there's value in measuring and understanding display ad engagement. In-ad interaction creates a point of reference that proves ads were visible. Attributing success to proven engagement creates greater certainty that display ads played a role in influencing conversions.