Channels & programmatic
Open exchange (RTB)
The open exchange is the open programmatic marketplace where any buyer can bid on any available impression in real time. It offers the greatest scale and the lowest CPMs, with the least control over inventory quality - which is why verification is considered mandatory there.
In practice
Open exchange suits scaled prospecting and retargeting where reach matters and every impression is verified for viewability, fraud and brand safety.
As quality requirements rise - premium environments, guaranteed placements, sensitive brands - buying moves up the ladder to PMPs and programmatic guaranteed.