We recommend this visually engaging video from the media literacy organization Commonsense Media:

The video uses analogies to tangible physical processes and objects like footprints, photocopiers, and jumbotrons to make its point succinctly and memorably. (Not all of the analogies are perfect — web search is much more flexible than a stationary searchlight — but few analogies are!)

For accessible explanations of the technical factors behind the points this video is trying to get across, see the web pages for “You’re Leaving Footprints” and “Sharing Releases Control” on this website.