Metrics
Y2 (search-arbitrage spread)
The day-2 retention of revenue after traffic cost — search-arb gross margin.
'Y2' is search-arb operator slang for the gross margin per session after netting traffic acquisition cost. A 30% Y2 means $1 in revenue produced $0.30 of operator margin after the native ad bill. Y2 is the number search-arb operators look at first thing every morning — it's the equivalent of CAC payback in subscription land.
Example
Yesterday: $11,400 spend, $14,920 RSOC payout. Y2 = 31%. The operator pulls the worst three campaigns dragging Y2 below 25% blended.