Madrid's underground carries more than 2.3 million riders a day, but advertisers had decided subway ad space was less relevant and effective than street-level billboards, and subway ad investment fell 7% in 2023. The usual response — sales decks citing reach numbers, discounted rate cards — hadn't reversed the perception.
JCDecaux Spain had hundreds of unsold ad spaces sitting empty across the network at any given time, generating no revenue and proving nothing to skeptical brands. A conventional pitch would tell a brand what the space could do; nobody had used the empty space itself to demonstrate it live.
David Madrid filled JCDecaux's unsold subway ad spaces with the Instagram posts of a real, unknown woman — 28 followers, no fame, no story — and let the campaign run as her account grew, using the ad space as the mechanism of her fame rather than describing the space's reach in a pitch.
Filled unsold subway ads with a real unknown woman's Instagram posts, letting the space itself make her famous—verifiable proof that replaced a sales pitch.
The campaign used space that was otherwise empty, so the proof cost almost nothing.
Anyone could watch Marina's follower count grow in real time, making the claim undeniable.
The human story of a nobody becoming famous made the campaign newsworthy and shareable.
Earned media amplified the reach, multiplying the effect without extra ad spend.
When buyers distrust your claims, use your idle inventory to run a live, verifiable demonstration instead of pitching numbers.
More than 400,000 impressions in the first week and interactions with 92,000 unique accounts within a month, per JCDecaux's own release; Marina's Instagram grew from 28 followers to over 10,000. Neither source read for this case discloses a brand-signing or media-investment figure, so that claim is not made here.
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