Privacy · Updated 12 Nov 2026

What the Library stores, and why

The Useful Library is run by The Useful Media Co (Raja, Chennai, India). Questions or deletion requests: [email protected] or the contact page.

On your device

Your game results, streak, stamps, shelf, checklists, 30-day tests and theme choice are saved in your browser's local storage. They never leave your device unless you choose Save my progress. Clearing your browser data removes them.

Save my progress

If you save your progress, we store your email, a scrambled version of your PIN (never the PIN itself) and your Library progress on Cloudflare, so you can load it on another device. You can delete it any time: open the menu, tap Save my progress, then Delete my saved progress.

Email lessons

If you sign up for the lessons, or save your progress for the first time, your email is added to The Useful Life newsletter on Beehiiv. Every email has a 1-click unsubscribe link.

Search

When you type into the search box, your words are sent to our search service on Cloudflare to find the best matches. We don't attach them to your name or email.

Bot checks and analytics

Signup forms use Cloudflare Turnstile to block bots. We use Cloudflare Web Analytics, which counts visits without cookies and without tracking you across sites.

Book links

Some book links go to Amazon. As an Amazon Associate, The Useful Library earns from qualifying purchases. Amazon handles anything you do on its site under its own privacy policy.

Your rights

You can ask to see, correct or delete any data we hold about you. Email [email protected] and it will be handled within 30 days.