Promo codes and vanity URLs

Setup that survives contact with listeners

Code hygiene rules: short, phonetic, one word (SHOW20 beats PODCAST-SUMMER-2026), unique per show, never reused across channels, and live before the spot airs. The vanity URL (yoursite.com/show) should redirect to a landing page that repeats the offer, because half your listeners will remember the show name and nothing else. Log both paths separately: code redemptions and vanity-URL sessions are different signals of the same spot.

What the discount costs: worked

The math from the DTC playbook, expanded: at an $80 AOV with 60% contribution margin you clear $48 per order pre-discount. A 15% code ($12) leaves $36; a 20% code ($16) leaves $32; a 25% code ($20) leaves $28. Now stack the media cost: if your modeled CAC from the Test Modeler is $120-130, a first order at $80 AOV loses money at any discount depth, and the test only pays on repeat purchase. That is not a reason to skip podcasts; it is the honest structure of the model, and your CFO should see it stated, not discover it.

Leakage, without a fake constant

Some listeners hear the spot, visit directly, and pay full price: attribution leakage. Measurement vendors publish multipliers claiming to correct for it; the multipliers are contested and methodology-dependent, so this site declines to bless one. Handle it as method, not arithmetic: report code CAC as measured, note the direction of its bias (overstates true CAC), and if the readout matters enough, add the pixeland a “how did you hear about us” question to triangulate.

Reading per-show CAC

Per-show CAC = show spend ÷ code redemptions. On the $2,500 two-show test, $1,250 per show and 8 vs 14 redemptions reads as $156 vs $89 CAC: a clear winner, small samples acknowledged. The three-way catch matrix: codes catch discount-motivated buyers, vanity URLs catch the show-name rememberers, the survey question catches everyone else willing to tell you. Run all three; they cost nothing.