Ad slot decay down the page

Ad slot decay down the page
Viewable CPM (cost per thousand viewable impressions) collapses by position. Same page, same demand.

— Slot 1 (above fold) $4.20 ▮▮▮▮▮▮▮
— Slot 2 $3.10 ▮▮▮▮▮
— Slot 3 $2.05 ▮▮▮
— Slot 4 $1.30 ▮▮
— Slot 5+ $0.85 ▮

n=95 sites, 28d. Each slot down the DOM loses ~28% CPM, because viewability (% of pixels in-view ≥1s) and dwell both fall. Slot 5 isn't free money — it's 20% of slot 1 while adding layout weight.

So what: three strong slots beat six weak ones. Pruning slots 5+ usually costs