[stevesearer]

While not a platform, my site sells and hosts our own advertisements which are only static images and are sold per month. We've been doing this for the last 5 years or so and it seems to work well for our advertisers.

Selling advertisements based on impressions incentivizes publishers to maximize impressions through various means such as click-bait titles, auto-refreshing ads while you're on the page, or implementing slideshows. All of these things degrade a website's experience in the long-term for the sake of ekeing out a few more dollars in the short term.