What is the spread in search arbitrage?
The spread is the difference between what a visitor earns and what that visitor cost. If, for example, a visit costs 10 cents and earns 13 cents on average, the spread is 3 cents, or 30% on spend. Spreads are thin, move daily, and can disappear when ad prices rise or feed payouts fall.
The spread is measured per visit, so compare like with like: CPC paid to the traffic source against RPV earned from the feed. Many dashboards call the earning side RPC, which causes confusion because RPC can also mean revenue per paid ad click.
Because the margin on each visit is a few cents, the business depends on volume and on speed of reaction. An illustrative campaign with a 3 cent spread needs 100,000 visits to make $3,000 before tools, staff and clawbacks. A 20% drop in feed payout would turn that same campaign into a small loss. This is why operators track unit economics by the hour rather than by the month.