There are several virtual caches on property. These are rather different from the standard geocaches.
Geocaching (Gee-oh-cash-ing) is something of a worldwide treasure hunt. A geocacher gets coordinates and clues from geocaching.com. They use these, in conjunction with a GPS unit, to search the cache, or, "treasure." Sometimes, there are multiple steps involved in the search, all of which are noted on the website. Most often, the geocache is a small container that includes a logbook of people who have found the cache. Sometimes, there are also small items, such as coins, pins, patches, toys, etc. Geocaching etiquette states that if you wish to take something from the cache, you leave something of equal value in its place (sort of like high-tech, long distance pin trading, if you will). Caches are usually in somewhat out-of-the-way areas, such as parks or trails. Chances are good that there are several in your area. Once a person has found (and replaced) the cache, he or she registers their find on the website.
The caches on Disney property are a little different. Virtual caches have no physical container to search for. Generally, the coordinates point to a particular location. The person looking for the virtual cache must take a picture or answer questions about the location to get credit for the find.