HB is an advanced programmatic advertising technique that allows publishers to offer their ad inventory to multiple demand sources (ad exchanges, SSPs, and DSPs)
Traditionally, publishers used the "waterfall" method, where ad calls went to one demand source at a time. This often-left money on the table because higher bids from other partners were never seen.
With header bidding, all demand partners bid at the same time, and the highest bid wins — leading to better competition and higher revenue for the publisher.
