Keep Calm And Monetise.
Marketing is all about creating a sense of scarcity through functional differentiation or pricing. That gets harder in the world of abundance that characterises free or freemium business models. It gets harder still in the world of phone apps.
Calm.com had a problem. They were an early entrant into the mindfulness space. They were run by seasoned entrepreneurs. They provided their users with daily meditation guides. Daily meditation guides that too many of their users downloaded to their devices and didn't use.
Because signing up to a mindfulness app doesn't make you a practioner. And if you're not an active practitioner you're not much use as a prospect for upgrading to profitable, premium offerings.
Their solution is an elegant product hack. By making the downloads last only 24 hours, they created genuine scarcity. You no longer have a phone full of unused meditation guides, you now have one meditation guide that will disappear if you don't get serious about this mindfulness thing.
If you're not serious about meditation, this might irritate you a little, but that's presumably your default state so no problem there. But, if you're serious or want to be, it is exactly the kind of prompt that might nudge you to make the effort to practice daily. It's not a restriction, it's an encouragment.
Soon enough, you appreciate that Calm.com are actually helping you towards your goal. By doing so, they're also helping you towards their goal. Which is one reason why they're already profitable and have multi million dollar revenues.
Marketing is about changing behaviour; changing behaviour is about creating habits; and creating habits is about interaction. And this is a simple reminder that product is the first P of marketing.