Almost all advertising systems/platforms today self-optimize when you are bidding against other advertisers vying for limited ad space. It doesn't matter how y

Almost all advertising systems/platforms today self-optimize when you are bidding against other advertisers vying for limited ad space. It doesn't matter how you bid because at the end of the day there is an expected revenue per impression (or per thousand like an RPM) that is used to determine how much exposure you get. For example: CPC - You bid $1 per click to a sign up page for more information on your product. You get a conversion rate of 10% so after spending $10, you get one sign up and the CPA cost of that lead was $10. CPA - You bid $5 per lead on the same system and observe the same conversion metrics. Now assuming the clickthrough rate was the same on that ad network, they only made $5 after the same number of impressions shown vs. the CPC model. The effective CPC they made from sending over 10 clicks was $.50 instead of a dollar. The ad platform will eventually optimize itself to give you a lower share of impressions if you bid the $5 CPA because it can normalize expected revenue/returns regardless of bidding models. This is why with a lot of CPA deals, they require a test period to suss out the economic viability of your bid before they will commit to delivering a large amount of impressions on a CPA model on your behalf.