Labels: [Sourced] checked against a source listed at the end. [General] standard industry knowledge. [Our view] opinion, labelled as such. [Illustrative] made-up numbers to teach an idea.
1. The story: "Half the money I spend on advertising is wasted"
The line is often attributed to department-store founder John Wanamaker: roughly "half the money I spend on advertising is wasted, and the trouble is I don't know which half." Quote Investigator found the earliest match in a 1919 speech where a minister credited it to Wanamaker, who died in 1922; no direct citation from Wanamaker himself exists, so the attribution is uncertain. [Sourced: Quote Investigator] It is a fine story about the problem, and an honest one about how often the stories we love are not provable. [Our view]
2. The one idea
Retail marketing tries to bring the right shopper to the right product at a price that makes money. The newest twist is that retailers now sell advertising themselves, because they own the place where shoppers decide and the record of what they bought. [General]
3. The kitchen-table version
A grocery store sells shelf end-caps to brands. Online, that is a "sponsored" spot in search results, and the store can tell the brand if the ad led to a sale.
4. The marketing toolkit [General]
Owned (site, app, email, loyalty), paid (search, social, retail media), earned (reviews, press), in-store. The metrics: customer acquisition cost, conversion, repeat rate, lifetime value, return on ad spend (ROAS).
5. Retail media
eMarketer forecast more than $10 billion of incremental US retail media spending in 2025, with retail media search ad spend closing in on $40 billion and display approaching $23 billion. [Sourced: EMARKETER, Jan 2025 forecast; a forecast by an analyst firm] Its later analysis says Amazon and Walmart take most of the growth. [Sourced: EMARKETER H2 2025 headline]
6. Worked example: ROAS vs real value [Illustrative, computed by script]
A brand spends $10,000 and the platform reports $40,000 of sales: ROAS 4.0. At 40% gross margin that is $16,000 margin, so profit $6,000. But if only 40% of those sales would not have happened anyway (incremental), real sales are $16,000, margin $6,400, profit -$3,600, incremental ROAS 1.6. Same ad, opposite verdict. This is why measuring incrementality (a control group that sees no ad) matters more than the reported ROAS. [Our view]
7. Privacy and trust
Retail media uses first-party purchase data; rules differ by region. Be clear in your policy about what you collect. [General]
8. Where AI fits
- Creative generation and testing. [General]
- Bidding and budget allocation. [General]
- Shoppers asking AI assistants instead of searching: marketing to the assistant (Module 21). [Our view]
9. Exercise
Think of the last ad that worked on you. Would you have bought anyway? How would a store know?
10. Quiz
- What does ROAS measure? Reported sales per ad dollar.
- Why can a high ROAS mislead? Many sales were not incremental.
- Why are retailers good ad sellers? They own the shopping moment and purchase data.