"Twitter 360 is a new application specifically developed for the iPhone 3GS that enables you to visualize your Twitter friends located in your nearby environment, thanks to a unique Augmented Reality functionality using the iPhone camera.
Twitter 360 is one of the first iPhone applications to use the new Twitter's Geotagging feature to geotag your tweets. Please, note that Twitter 360 does not intend to be a fully Twitter client, our goal is to provide a different approach to the Twitter experience. We are already working on new ideas to be added in this application."
"In August  we announced that we were working on a new API that would provide developers with the ability to geotag tweets. Today, the Geotagging API is officially available.
This release is unique in that it's API-only which means you won't see any changes on twitter.com, yet. Instead, Twitter applications like Birdfeed, Seesmic Web, Foursquare, Gowalla, Twidroid, Twittelator Pro and others are already supporting this new functionality (go try them out now!) in interesting ways that include geotagging your tweets and displaying the location from where a tweet was posted. The added information provides valuable context when reading your friends tweets and allows you to better focus in on local conversations. Now you can find out what live music is playing right now in your neighborhood or what people visiting Checkpoint Charlie are saying today about the anniversary of the Berlin Wall. These are only the beginning and we are really looking forward to seeing the creative uses emerge from the developer community.
It's important to note geotagging is disabled by default for all users which means you will need to opt-in in order to use it. To activate the new geotagging functionality, go to your Settings page and click 'Enable Geotagging'."
(Twitter.com, 19 November 2009)
"Airwave1 is a complete GPS L1 receiver and it is the first product to benefit from Air's Always-On™ GPS technology.
Airwave1 is designed to support geotagging in digital cameras. To support this application, location information needs to be provided instantly when the user takes a photograph. With Airwave1 inside, the camera is continuously aware of its location and so it can immediately tag a photograph with its location - as soon as it is taken.
Airwave1 is a complete system for continuous location in cameras, comprising RF, analogue and digital signal processing hardware, a microprocessor and all embedded software necessary to provide a complete 'antenna to coordinates' solution in a single-chip."
(Air Semiconductor Inc.)
Gerrit Visser (December 17, 2003)
The New Scientist writes on the UK service TagandScan "By tagging messages to mobile phone "cells", users can post reviews, leave notes for friends, or even organise demonstrations".
When a user logs onto the TagandScan site using their cellphone, they can opt to be automatically located according to network cell from which they are calling. They can then create a message or view ones already left in that cell by other users.
TagandScan was created by New York company Cimarrones and has been undergoing UK field trails for the past month. Cimarrones' president Ryan Janssen says he has been surprised by the ways people have used the service in testing.
"We had some preconceived notions but people are using them in ways we never intended," Janssen told New Scientist.
Janssen believes people may also use TagandScan to organise political gatherings or create their own guides to a city's bars and restaurants.
Full article in New Scientist
J. C. Spohrer
As global positioning, wireless communication, and mobile display technologies continue to advance, our notion of place will change. Information objects--first geocoded signs and later animated special effects--will begin to populate real physical space on what we call WorldBoard channels. WorldBoard is a proposed global infrastructure to associate information with places and ultimately to provide people with enhanced information perception services.