Geocaching
is an outdoor recreational activity, in which participants use a Global Positioning System (GPS) receiver or mobile device and other navigational techniques to hide and seek containers, called "geocaches" or "caches", at specific locations marked by coordinates all over the world.
Geodashing
is an outdoor sport in which teams of players use GPS receivers to find and visit randomly selected "dashpoints" (also called "waypoints") around the world and report what they find. The objective is to visit as many dashpoints as possible. Unlike geocaching, nothing is to be left at the dashpoints; the sole objective is to visit them within the time limit. Players are often encouraged to take pictures at the dashpoints and upload them to the site.
Geohashing
is an outdoor recreational activity inspired by the webcomic xkcd, in which participants have to reach a random location (chosen by a computer algorithm), prove their achievement by taking a picture of a GPS receiver or another mobile device and then tell the story of their trip online. Proof based on non-electronic navigation is also acceptable.
Geohashing divides the earth into a grid made up of graticules which are one degree wide in latitude and longitude. Inside these graticules, a random location is set. Geohashers then have the opportunity to go at the chosen location, either inside their own graticule or in a nearby one. If the location is inaccessible or in a private area, geohashers are advised not to try to reach it, although obviously inaccessible locations have been reached several times. In addition to the repeating location in each graticule, each day there is a single global hashpoint, much more challenging to reach.
Whereas other outdoor recreational activities like geocaching have a precise goal, geohashing is mainly fueled by its pointlessness, which is deemed amusing by its players. The resulting geohashing community and culture is thus extremely tongue-in-cheek, supporting any kind of humorous behavior during the practice of geohashing and resulting in a parody of traditional outdoor activities. Navigating to a random point need not be pointless.