The Zam-Buk green book of prophecies, 1923
The pattern
This still is filed under Utility premium.
Define
The free thing is kept because it works (a calendar, a tool, a template) and the brand rides along.
Mechanism
Usefulness as media. Frequency of use is frequency of exposure. Distinct from a keepable card: here the object has a job.
Verdict
We can give something people will actually use next week.
Why it works
It is a genius engagement mechanism: by paying people to hunt for and transcribe testimonials, they are actively convincing themselves of the product's miraculous powers.
Steal this when
You want to incentivize deep engagement with your marketing materials by gamifying the reading of testimonials.