The ad that fits too well

You're sitting over a coffee. You tell a friend your lower back's playing up again and you really should get a proper office chair. No typing, no Googling — just a chat.

Two hours later, Instagram:

"Ergonomic office chair — 30% off today"

You pause. Did my phone just listen to me?

Probably not. What happens far more often: the platform knows enough about you to serve that ad without ever switching on a microphone. It knows your age, your postcode / ZIP, how often you sit on the sofa (step counter), your recent back-related Google searches, the apps on your phone — and it knows your friend and her search history too.

This isn't a conspiracy. It's the business model.

In this module we'll look at what platforms actually know, how free services are really paid for, and — more importantly — what you can switch off in the next 20 minutes to silence a big chunk of it.