A guide to consumer devices and services, and the types of data they collect.
Web browsers create records of sites you've visited.
Google, Bing and other search engines can record the types of searches you're performing, sometimes keeping them for many years.
Commerce websites like Amazon.com often keep detailed records of past purchases to be able to recommend items you might like.
Many online advertisements, when clicked, make a note of the types of products you might be likely to buy.
Social networking sites like Facebook record usage patterns such as the photos you've looked at and whose profile you've viewed.
Smartphones record your location as you move around, both to find you when you have an incoming call and to offer map-based services such as driving routes and lists of restaurants that are near you.