What we store, in plain words.
STEMLinePK has no accounts, no sign-up form and no analytics. Nothing you do here — the topics you open, the quizzes you answer — is sent to a server, because there is no server to send it to. The site is a set of static files. It does carry one advertisement, which is described in section 8.
LAST UPDATED 2 SEPTEMBER 2026
The short version
We do not know who you are, where you are, or what you studied. We cannot, because we never collect it. Your progress lives in your own browser and is deleted the moment you clear your browsing data.
The fonts are served from this site rather than from Google, so simply reading a lesson contacts nobody. Two things can load from elsewhere: a single advertisement on a course page, and YouTube if you press play on a video. Both are described below.
1. Who this policy is from
STEMLinePK is an independent educational website run by a single teacher, producing free study notes for Punjab Board, Cambridge O Level and Cambridge A Level students. It is not affiliated with, endorsed by or connected to Cambridge Assessment International Education, the Punjab Curriculum and Textbook Board, or any examination authority. Contact details are on the contact page.
2. Personal information we collect
None. There is no registration, no login, no newsletter, no comment box and no contact form anywhere on this site. We never ask for your name, email address, phone number, school, date of birth or payment details, and there is no mechanism here that could receive them.
If you choose to email us, we will have your email address and whatever you wrote in the message — because that is how email works. We use it to reply to you and nothing else. We do not add you to a mailing list and we do not pass it to anyone.
3. What is stored on your device
The site saves your progress using your browser's local storage. This is not a cookie: it is never transmitted with your requests, it is not readable by other websites, and we have no way of reading it ourselves. It stays on the device you used, in the browser you used.
| Key | What it holds |
|---|---|
stemline.v1 | Your level, which topics you have completed, quiz scores, flashcard progress and your sound preference. |
stemline.v1.work | Answers you typed into exam questions, so they survive a page refresh. |
stemline.booted | A single flag so the start-up animation plays once per tab rather than on every page. |
stemline.draft.v1stemline.draft.videos.v1stemline.admin.ok | Used only by the site author's private editing tools. These are never created by normal browsing. |
None of this is personal information, none of it is transmitted, and none of it is used to identify or profile you.
4. Cookies
This site sets no cookies of its own — not for analytics, not for preferences. Two third parties may set their own: the advertising network when an ad loads (section 8), and YouTube if you deliberately play an embedded video (section 6). Neither is readable by us.
5. Analytics and tracking
There are none. No Google Analytics, no Meta pixel, no heatmaps, no session recording, no fingerprinting and no third-party tracking scripts of any kind. We genuinely do not know how many people visit this site or which pages they read, beyond whatever our hosting provider records (section 7).
6. Third-party services
Two external services can be involved, and neither of them is contacted unless you deliberately click something. Simply reading a page here sends no request to anyone but this site.
Fonts — served from this site
The typefaces are hosted here rather than loaded from Google Fonts. This matters more than it sounds: a site using Google Fonts hands your IP address to Google on every single page view, before you have clicked anything. Ours does not, because that request no longer exists. The fonts are Chakra Petch and IBM Plex, both released under the SIL Open Font License.
YouTube — only when you click
Video lessons show a still thumbnail rather than a live player. No
YouTube script or cookie loads until you actually click play. When
you do, the video is embedded through
youtube-nocookie.com, Google's privacy-enhanced mode, which
avoids setting tracking cookies unless you interact further with the player.
Once a video is playing, Google's own privacy policy applies to it. The
thumbnail images themselves are loaded from img.youtube.com.
Google Drive — only when you click
Some lessons link to downloadable notes hosted on Google Drive. Nothing is requested from Drive unless you follow one of those links, at which point you are on Google's site and their terms apply.
7. Hosting and server logs
The site is served as static files by a commercial hosting provider. Like every web host, it automatically records standard technical request data — IP address, time, page requested, browser type — for security and to keep the service running. These logs are held by the host under their own policy, are retained for a limited period, and are not something we read, export, analyse or combine with anything else.
8. Advertising
This site carries advertising, supplied by Adsterra, to keep the notes free. Banners appear on the course pages, beside the notes download, and on the lesson pages: above the lesson, once part-way through it, before the practice questions, after the quiz, and in the sidebar on a wide screen.
Like any ad network, Adsterra receives your IP address and basic browser information when an ad loads, and may set its own cookies or similar identifiers to decide which ad to show and to count it. That happens under Adsterra’s own privacy policy, not ours, and we receive none of it — we cannot see who you are from an ad any more than from anything else here.
Pop-ups and pop-unders are switched off, and so are the push ads that ask to send you notifications after you have closed the tab. Those are the formats that pay best and they are not worth what they cost a reader.
We are currently trialling a floating ad that sits over the page rather than inside it. It is being assessed and may be removed. You should know two things about it while it is here: it can take the appearance of a message or a notification, and it is an advertisement whatever it looks like. Nothing on this site will ever message you, so treat anything that appears to as an ad.
Gambling and dating adverts are blocked on this site at the account level. We do not, however, review individual adverts before they appear — the network chooses them, in the moment, per reader, and category blocking relies on the network having labelled its own stock correctly. That is the honest limit of what we control: we choose the network, the formats and the categories, not the adverts themselves.
If you see an advert here that is inappropriate for a study site, please tell us. That is worth knowing about and will be acted on.
9. Children and students
Much of this site's audience is school-age, and many readers are under 18 or under 13. This is precisely why the site collects no personal data: there is nothing to consent to, nothing to leak, and nothing a parent or school needs to request the deletion of. We do not knowingly collect information from anyone of any age, because we do not collect information at all.
10. Your rights and how to erase everything
Data protection laws — including the GDPR in Europe and the UK, and comparable rules elsewhere — give you rights to access, correct, export or delete personal data held about you. We hold none, so there is nothing for us to hand over or erase on request.
To delete everything the site has saved on your device, clear your browser's site data for this domain, or open the site in a private window and it will store nothing beyond that session. Your progress will reset, which is the entire mechanism.
11. Links to other sites
Lessons occasionally link to exam boards, reference material and other educational resources. Once you follow such a link you are on someone else's site, governed by their privacy policy, and we have no control over and take no responsibility for how they handle your data.
12. Changes to this policy
If what the site does changes, this page changes with it and the date at the top is updated. The most likely reasons for a future change are the addition of advertising or of privacy-respecting visitor statistics, and both would be described here explicitly before being switched on.
13. Contact
Questions about this policy, or about anything on the site, can be sent to stemlinepk@gmail.com.