Publisher / Media

Publishers package inventory (placements, formats, floors) and connect to demand through direct deals, ad networks, SSPs, and exchanges. They:

• Decide where ads can run and how dense the page or feed can be.
• Set commercial rules (floors, blocklists, brand safety).
• Compare channels and partners by yield.
• Balance short-term revenue against long-term engagement.

Their product is not “ads” alone — it is attention inventory that must stay valuable to users and buyers.

Seller-side metrics focus on was the slot filled and how much did we earn:

• Fill rate — share of requests that become paid ads.
• eCPM / RPM — revenue efficiency per thousand impressions or pageviews.
• Viewability — were ads actually on-screen?
• Ad density — how much of the experience is ads vs content.
• IVT rate — invalid / non-human traffic risk.

High fill with low eCPM (or high density with poor engagement) is a classic publisher trade-off.

Publishers sit upstream of the auction stack:

• SSPs / ad networks aggregate their inventory and run seller auctions.
• Exchanges (ADX) match that supply with buyer bids.
• Advertisers (via DSPs) compete for the impression.

A publisher-facing dashboard number is often not the same as the advertiser’s cost metric — even when names look similar.

• Chasing fill rate alone and flooding the page with low-value ads.
• Ignoring viewability when selling “impressions.”
• Raising floors without watching bid density and unfilled demand.
• Mixing RPM and eCPM definitions across tools.