Privacy

Last updated 29 October 2026

The short version

You can use the free parts of criticalmassbook.com without an account. If you buy Full Access, we keep only what is needed to run your account: your email address, your plan, and a securely scrambled copy of your password. We never sell or share your information.

Paying

Payments are handled by Gumroad. Your card details go to Gumroad and its payment processors, never to us. Gumroad tells our site your email address, your license key and whether your membership is active, so we can open the right quizzes for you. Gumroad’s own privacy policy applies to the checkout.

Your account

We store your email, plan, membership status, sign-in times and a hashed password (we cannot read your password).
We use your email only for account messages: setting or resetting your password and confirming your access. No newsletters unless you ask for them.
A small cookie keeps you signed in. It is not used for tracking or advertising.
To close your account and delete your details, email us or reply to any account email.

Quizzes

Quizzes run in your own browser. Your answers and scores are not sent to our server. A name you type for a certificate is used only on your own screen.

Server logs

Like almost every website, our host records basic technical details when a page is requested (address, browser type, page and time) to keep the site running and secure.

Children

The site is meant for adults and does not knowingly collect information from children.

Changes

If this policy changes, the date at the top will change with it.