Preferred publisher sets a higher cpm but it’s fixed & in a priority tier above private auction. Publisher advantage is a fixed rate that would be higher than they’d get in private auction Buyer advantage buying at a fixed price vs against fluctuating floors. Publishers will have different priority settings but as an example it might look like: Direct & programmatic guaranteed (fixed price guaranteed inventory) Preferred (fixed price un guaranteed ) Private auction (floor price un guaranteed) Open market ( floor price un guaranteed ) I’d suggest a buyer to ask for both and testing win rates & ecpms More on reddit.com

Agree with hankiestpank. Illustration of his explanation here: http://marketingland.com/wp-content/ml-loads/2015/05/centro-private-marketplace-preferred-auction-deal-id-800x534.png More on reddit.com

everything pretty much operates in a waterfall (even header bidding) and CPM is pretty much the competing point across everything (and sometimes publisher politics :) ). Direct sold generally sits above everything and will get the first look either because it's the higher CPM or part of the deal structure with the buyer that they get first look. Preferred deals are similar to direct sold whereby someone agrees to buy X impressions at Y cpm with the exchange being the place where the deal is brokered vs humans hashing it out. A preferred deal can (at times) have a higher CPM than the direct sold and will go ahead of the direct sold) Private auctions would be where a publisher sets a certain amount of inventory (generally higher up in the fall) available in exchange and only allows a small number of buyers bid on it and most times there's floor price set that's higher than the cost in the open exchange because the inventory is perceived to be more valuable Header bidding is suppose to create better competition and eliminate waterfalls but the waterfall part is only partially true in a lot of cases - the inventory sent to the exchange has already participated in a waterfall set by the publisher within their adserver. They have already said "this piece of inventory is priority 1 for direct sold, this is priority 2 and for preferred deals, etc..." all the way until it gets to a prioritization assignment for the exchanges and then that goes to the exchanges and the header bidding will do it's thing and try to find the best price for everyone. Hope this helps More on reddit.com

I do not like this option if you are referring to Open Auction Buyer Optimization, which lets open auction compete against private. It can get some incremental revenue but defeats the purpose of private, no? We had a buyer who was unhappy that we had this option checked...it was my fault because I did not notice it was enabled by default. More on reddit.com