HarperCollins Publishers Australia

HarperCollins Publishers Australia needed to seed a new reader sign-up destination, Book Bliss, with qualified members from launch. No first-party audience to retarget into, no existing community to convert.

The brief: hit a 9,600-click delivery KPI on an A$12,000 working budget, and turn that traffic into measurable cold acquisition that could scale into a repeatable channel for future series and reading-club launches.

Facebook was elected as the sole paid channel. Single-platform discipline meant the full budget sat behind a stratified audience architecture instead of fragmenting across networks. Nine ad sets were built across three audience types.

Modelled audiences carried the heaviest weight: a Look-A-Like Audience seeded from HarperCollins's existing reader data, plus an Opt-in Look-A-Like seeded from email subscribers. A first-party Custom Audience was built from the existing CRM. Six interest-based prospecting sets ran underneath, weighted toward women aged 20 to 50 with declared interest in reading or publishing, with two control sets for AU women in publishing-adjacent roles and male reader segments.

Each ad set carried its own creative variant tied to the audience's likely affinity. Spend was front-loaded to the modelled and first-party audiences (the two most likely to convert efficiently) with the interest-based sets running as a control to map the audience's actual shape against the seed.

The five-week flight delivered 2,452 Book Bliss club sign-ups at an average CPA of A$4.82. 9,806 clicks were served at a 2.05% click-through rate, beating the contracted 9,600-click KPI by 2.1%. The campaign reached 264,617 unique Australians.

The audience architecture proved out. The Look-A-Like Audience alone, taking 53.2% of the Facebook budget, delivered 58.5% of total sign-ups at the campaign's lowest CPA (A$4.39) and highest click-through rate (2.69%). Combined with the Custom Audience, the two modelled and first-party constructs accounted for 1,899 sign-ups (77.4% of conversions) on 72.6% of Facebook budget. The six interest-based prospecting sets carried the remaining 22.6% of conversions and ran less efficiently, as forecast, but established a defensible audience-shape baseline for the next launch.

Mobile news feed delivered the dominant share of conversions. 2,264 of the 2,452 sign-ups came from women, and the men who did sign up clustered in the modelled and first-party audiences, confirming the seed data described the audience accurately rather than just biased it.