Why impression share matters
It answers the head’s question dashboards dodge, “can this channel give us more?”: high share means the well is nearly drained at current targeting and the next dollar buys diminishing scraps, low share means demand exists that budget or rank is leaving on the table. The lost-share diagnostics say which lever, money or quality, is doing the rationing.
Reading the diagnostics
- Share lost to budgetCampaigns capping out while demand continues, a funding decision
- Share lost to rankBids or ad quality losing auctions, a craft decision
- Segment itBrand terms deserve near-total share, generic terms earn theirs by economics
- Track it with CPCsBuying the last shares of an auction gets expensive nonlinearly
Questions
Should impression share be maximized?
Only where the economics hold: chasing total share on broad terms buys the auction’s worst impressions at its highest prices. The strategic use is defensive floors on brand and high-intent terms, and headroom measurement everywhere else.
Where does impression share apply beyond search?
Anywhere eligibility is measurable: shopping placements and some social auction reporting expose share-like metrics, and the logic transfers, reach against addressable audience is the same question wearing each platform’s units.