The Drum takes a look at header bidding, which it says has "proven to be one of the key areas of debate in the ad tech space this year, having been pushed heavily by prominent ad tech vendors, including AppNexus and Rubicon Project to name a few." But, it reports, "the momentum of the technology was disrupted earlier this year by arguably its biggest detractor Google, with its announcement of the full rollout of its answer to header bidding -- DoubleClick iFirst Look -- a solution that is now available to publishers worldwide, as well as the trial of exchange based dynamic allocation (EBDA)." Before both technologies came onto the scene, "many publishers looking to monetise their inventory using programmatic media buying technologies used a 'waterfall' of ad tech. This meant that they could receive monetisation assistance from a number of ad tech partners, i.e. where bid requests where passed by multiple ecosystems, oftentimes providing diminishing returns and hindering an optimum user experience."