Creator-Led Growth | World of Books Paid Social Case Study

What we were up against

World of Books is a sustainable platform for buying and trading secondhand and rare books, built around giving books a second life rather than sending them to landfill. For years its app installs and trades had been driven by Google Ads, while Meta sat dormant, untouched for more than three years.

Our brief was to change that, and to do it boldly.

For the first time ever, World of Books was willing to take a gamble on a 100% creator-led ad strategy to grow app installs across both the UK and the US. The thinking was simple to state and risky to execute: source authentic creators who genuinely matched the audience, cut through the noise, outperform polished corporate advertising, and prove that Meta could deliver efficient growth at scale.

Our target was to establish Meta as a core, scalable install driver, and eventually match the efficiency of Google Ads with an ambitious cost per acquisition, and keep cost per install at or below an industry benchmark.

All of this in the US, a fiercely competitive book-buying market where legacy giants leaned on corporate advertising and B2B partnerships, and direct competitors leaned on organic social, word of mouth and affiliates.

How we tackled it

We started with the audience, and reframed who it actually was. This was never just about book lovers, it was about people looking to make money and space.

The initial focus was deal-savvy parents and bargain-hunters across a wide age range, but World of Books' own first-party trade data revealed a second opportunity in both markets: students sitting on piles of expensive, single-use textbooks. Blending that persona research with first-party trade data and Meta's Advantage+ technology, we built four distinct, high-reach personas across both regions: deal-focused parents, textbook students, home movers and renovators downsizing their shelves, and trade lookalikes built from World of Books' existing customer data.

Because there is no single World of Books customer, polished corporate campaigns were never going to land the same way as real people with real books in their actual homes. So we went fully creator-led, partnering with Influee to source a diverse roster of creators reflecting each persona, from med students to eco-conscious parents. Bypassing in-house production turned this into a creative testing engine built for scale.

We've worked with eighteen creators across the UK and US so far, producing over two hundred ad variants, testing hooks, visual styles, copy approaches and even regional accents to see what actually stopped the scroll. The briefs leaned into relatable moments: clearing shelves after graduation, making space and cash at once, keeping books out of landfill.

That volume also solved the biggest operational risk: creative fatigue. In-house ads tend to stagnate quickly at scale, but an agile portfolio of creator content meant that the moment one creative dipped, we could rotate in a fresh face, a new hook or a different accent. In the US especially, leading with a creator-only strategy gave World of Books an instant, trusted voice in a crowded market, immediate reach through paid auctions paired with authentic storytelling, keeping relevance high and fatigue low.

What we achieved

In just four months, Meta went from a dormant channel to the second biggest driver of app installs across both markets, behind only organic search in the UK and Paid Search in the US. And it scaled while getting more efficient, which is the hard part.

•Monthly app installs in the UK up 490%, with cost per install driven down 30% to below the £2 target
•US installs doubled inside two months, holding a sub-£1.75 cost per install throughout
•Spend scaled aggressively to match the demand, up 495% month on month in the UK and 305% in the US, without efficiency slipping
•Trades, the real commercial outcome, up 508% in the UK with cost per acquisition cut 32% and beating the £30 target, while the US brought a high initial acquisition cost down by a third in two months

The bigger win is what it did to the model. A channel that had been switched off for years has now become a core, scalable channel for new user acquisition. This approach and the campaign has reshaped how World of Books thinks about growth across its multiple markets.