Second-price auction

Bid ten, with a runner-up at six, and you pay six. The four you did not spend stays in your funded balance and buys the next placement.

Why is this used for advertising?

Because it removes the reward for guessing. First-price rules push buyers into shading their offers downward and re-tuning them week after week, which is work that improves nobody’s answers. Naming what a placement is genuinely worth is the sensible move here, so a campaign can be configured once and left alone.

What is a floor price?

The minimum an impression can clear at, regardless of competition. CrawlClick sets floors by the value of the moment, so a query-time crawl carries a higher floor than bulk indexing.

What happens when only one advertiser competes?

The lone buyer clears at the floor, since no rival offer exists to price against. Lifting that buyer’s maximum from ten to fifty changes the invoice not at all, because the amount charged is taken from the runner-up and there is no runner-up.

What if nothing clears the floor?

Nothing is inserted, and the crawler receives the publisher’s page exactly as written. An empty auction is silent in both directions: no charge, no accrual, no record of a placement that never happened.

Which number does the publisher earn from?

The clearing price, not the winning maximum. Doubling your ceiling without moving the runner-up leaves the publisher’s earnings untouched, which is why floors rather than enthusiasm set what inventory is worth in a thin market.

Why does GSP not change anything here?

Generalised second price exists to rank several slots against each other. CrawlClick serves one labelled passage per page, so there is a single slot, and the generalised form collapses back to the plain Vickrey case described above.