This is an excerpt from Geocaching for Schools and Communities by J. Kevin Taylor,DuAnn Kremer,Katherine Pebworth & Peter Werner.
A geocache, pronounced "geo-cash," is a hidden store of trinkets. The word geocache comes from geo, meaning "of the earth," and cache, which is French for hiding place or hidden store. Simply stated, geocaching involves someone hiding a box of trinkets and posting the coordinates of the box's location on the Internet; other people reference the coordinates and then go hunting for the trinkets. People who go geocaching are called geocachers (often abbreviated to cachers). If you want to go geocaching, you look up the coordinates of a cache, plug them into your GPS unit, and try to find the cache. A cache is normally well hidden so that people who are not actually looking for it don't find it by mistake; therefore, along with the coordinates, the person who hid the cache will usually post a short clue to help people locate the cache once they are within a few feet of the location.
So, you track down the location using your GPS and the posted coordinates, you solve the clue that was posted, and you find the cache. Now what? At a traditional geocache, most geocachers like to swap a trinket—that is, they take something from the cache and leave something in its place. Trinkets can be any small item worth no more than $2. Some creative cachers leave the same trinket every time, and this becomes a calling card of sorts. After finding a cache, most geocachers will log their cache online. They will also track the number of caches they have found. You don't have to log your cache if you prefer not to; some dedicated geocachers simply enjoy the thrill of hunting for a cache. Those who do log their find also sometimes leave comments for the person who set the cache. Geocachers may leave comments to thank the person for setting the cache, to compliment the person on a well-hidden cache, or to report any problems with the cache. An example of a reported problem might be that the cache wasn't properly hidden after the last find. When reporting this problem, the geocacher may include a request for future geocachers to be careful in rehiding the cache more thoroughly. More details on the intricacies of geocaching are covered throughout the book.
Although more than one Web site is available for looking up and logging a geocache, the most popular site by far is www.geocaching.com. To use the geocaching.com Web site, you set up an account with a user name and password of your choice. A basic account is free and gives you everything needed to start caching. Frequent reference will be made to this Web site as we explore the many intricacies and complexities that have been added to the basic concept of geocaching. Throughout this text, any further mention of logging a cache or looking up a cache on the Internet refers to the geocaching.com Web site unless stated otherwise.