Internet object tracking

thumb|upright|A geocache concealed behind a sign in the Erratic Rock State Natural Site state park 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. The first geocache was placed in 2000, and by 2023 there were over three million active caches worldwide.

thumb|A Bookcrossing in Leipzig southwest of Berlin, Germany, December 2009 thumb|Bookcrossing in Lyon northeast of Nîmes, France, May 2006 thumb|A Bookcrossing at Kozminski University in [[Warsaw, May 2019]]

Postcrossing is an online project for people to exchange postcards with other project members globally. The project's tag line is "send a postcard and receive a postcard back from a random person somewhere in the world!" The name Postcrossing is a union of the words postcard and crossing, and its origin "is loosely based on the Bookcrossing site".

AirTag is a tracking device developed by Apple. AirTag is designed to act as a key finder, which helps people find personal objects such as keys, bags, apparel, small electronic devices and vehicles. To locate lost or stolen items, AirTags use Apple's crowdsourced Find My network, estimated in early 2021 to consist of approximately one billion devices worldwide that detect and anonymously report emitted Bluetooth signals.

EuroBillTracker (EBT) is a website designed for tracking euro banknotes. It was inspired by the US currency bill tracking website Where's George? The aim is to record as many notes as possible to know details about their distribution and movements, follow it up, like where a note has been seen in particular, and generate statistics and rankings, for example, in which countries there are more tickets. EuroBillTracker has registered over 243 million notes with a combined total value of more than €4.4 billion as of February 2026.

Munzee is a freemium scavenger hunt game where QR codes have to be found at different places in the real world. The game is similar to geocaching but uses QR code technology, in addition to device GPS location, to prove the find instead of a logbook. Launched in McKinney, Texas in 2011, the game caught on first in Germany, along with California and Michigan. It is now played in more than 188 countries around the world, and there is at least one physical Munzee deployed on every continent, including Antarctica.

thumb|A 2004 USA Geocoin

US dollar note tracking website

key finder

outdoor hobby

dog tag used in geocaching

process of tracking the movements of banknotes

thumb|A GeoKret GeoKrety (from Greek: geo, "earth" and Polish: krety, "moles") is an online tracking service targeted at Geocachers. Each registered object, called a GeoKret (plural: GeoKrety), has a unique tracking code, allowing its movements between locations such as Geocaches to be tracked and registered on the service. While the idea behind trackable items such as GeoKrety originated with the geocoin and travel bug, Geokrety is an independent trackable service that can be used with any geocaching activity.