Glossary of Mobile Advertising Terms
Header bidding (also known as pre-bidding or advance bidding) is a technology (you might also call it an advanced technique) that allows publishers to offer inventory simultaneously to multiple ad exchanges, before putting ad servers in play. To put it simply, header bidding gives publishers a lot more control over the selling of ad space (i.e. they can choose who to sell to).
With this “technique” publishers can also learn more about buying habits of different advertisers, which in turn can help them make more informed decisions. Also, impressions can be sold individually. In truth, you can think of header bidding as another auction which is placed in the header of a web page (outside of the ad server), and as such loads before anything else on the page.
For advertisers, header bidding allows them access to all of the publisher’s inventory, which means they’ll know everything that is available and at what price. Another feature of header bidding is that every advertiser will have equal access. As with everything, header bidding also has some issues. Probably the biggest one is the page load times (increased latency), although this might not always be the case (at least not in the way that would bother most people).