Publisher Side Ad Platform Statistics
This really shows the dominance of Google for display advertising, especially for smaller sites with their Adsense platform.
I’ve thought for a while that Facebook should be able to enter this market and using their vast amount of user data increase CPM’s for small publishers. As of yet this hasn’t been widely adopted and Adsense still dominates. Google also own Doubleclick which is used more widely by larger advertisers.
An update for June 2020. I’ve seen Facebook publisher ads at the top of the Google paid search listings now so they are actively targeting webmasters to grow their 3rd party ad platform.