One example I can think of in the Community is the use of Loyalty cards eg Woolworths Rewards Card. I might get 10% off a shop every time I scan but they also collect a lot of information from me about my regular weekly shopping and then target advertising at me online eg sales of my favourite items etc to entice me to buy more. A great video I found to show my Yr 6s-

Four Reasons to Care  About Your Digital Footprints. https://youtu.be/Ro_LlRg8rGg