How paid ads actually work

Every major ad platform runs an auction. Advertisers bid; the platform picks winners based on bid + expected outcome + ad quality. Understanding this mechanism changes how you think about targeting, bidding, and creative.

The auction in 60 seconds

When a user triggers an ad slot, the platform looks at every advertiser who's eligible to show. For each, it computes:

Expected revenue to platform = bid × expected conversion rate × ad quality

Highest expected revenue wins. The platform optimizes its own revenue, not yours.

What this means for you

• Creative quality matters more than bid. A cheap ad with 3x the CTR beats an expensive ad with 1x CTR.
• The algorithm gets smarter with data. Early campaigns perform worse because the platform has no signal. Feed it conversions quickly.
• Targeting narrows the pool. Tight targeting raises costs per impression but should improve conversion rate. Broad targeting is cheaper per impression but conversion depends on creative.
• Budget pacing matters. Sudden budget increases spook the algorithm. Scale gradually.

The modern shift: creative over targeting

Post-iOS 14 and signal loss, targeting is less precise. Platforms have shifted to creative-first: the creative itself does the targeting by resonating with the right audience. Broad targeting + great creative often beats narrow targeting + mediocre creative.