Location based information are not added to Twitter messages by default. A user needs to enable this option in the Twitter settings. Users who have enabled the option may, at some point, want to delete location information from their account to prevent tracking and an invasion of their privacy.

This guide explains how to enable location information on Twitter, how to disable the feature again and how to delete all location information from past tweets.

You first need to visit the Twitter homepage to sign in to your account. Once signed in click the account username in the upper right corner of the screen and select Settings from the available options. You can also open the account settings directly by following this link (displays a sign in form if you are not logged in, displays the account settings otherwise)

Locate the Tweet Location setting under the Account tab. Location information are added to Twitter automatically if the setting “Add location to your tweets” is activated.

Ever had something you wanted to share (“fireworks!”, “party!”, “ice cream truck!”, or “quicksand…”) that would be better with a location? By turning on this feature, you can include location information like neighborhood, town, or exact point when you tweet.

When you tweet with a location, Twitter stores that location. You can switch location on/off before each tweet and always have the option to delete your location history.

Location information are only added to tweets if the device or application supports those information. When enabled location information are added below tweets of the user.

Tweets won’t include location information from that moment on if the service is disabled by the user.

Locate the “delete all location information” link on the same page to delete previous location information.

Twitter displays a popup that needs to be confirmed. Please note that it may take up to 30 minutes before the information are removed from the database and the tweets.

Want to know where Michael Arrington, Techcrunch founder was on January 23? In a building near the San Francisco airport. What did he wear? His urban spoon tshirt. Everyone can extract those information with the help of the software.

Creepy can also search for usernames on Twitter or Flickr. The software needs to be authorized before it can be used to search for Twitter users, the Flickr search on the other hand works right of the box.

The people tracker extracts the geolocation information from various sources.On Twitter,geolocation information added by mobile device tweets are used as well as IP address to location lookups if the web interface was used to write a message. For photos, both EXIF tags and geolocation information that are accessible through the image hosting services API are used

Creepy is actually making use of more services, not only Twitter and Flickr. It uses Foursquare as well but only for check-ins currently that are posted on Twitter, and more than a dozen image hosting services including Twitpic, Twitgoo or Img.ly.

The service displays the location of the user on Google Maps by default. This can be changed in the options to one of the other available services.

The effectiveness of the tracking depends largely on the user’s knowingly or unknowingly use of the service’s geolocation feature.

Is the use of the application legal or ethical? The geolocation data is freely accessibly, all that Creepy does is provide an optimized interface that collects and displays all relevant information directly.

Privacy conscious users may want to test Creepy by searching for their own accounts to see if they reveal any information that they do not want to reveal to the public.

Creepy can be downloaded from the developer website over at Github.

Geolocation has been added to make use of the user’s location when providing services to the user. This feature can be integrated into websites and extensions.

The user’s privacy is guaranteed since a confirmation prompt is displayed whenever a service tries to access the geolocation feature to detect the user’s location.

The geolocation feature is for instance used in Google Maps to locate the user on the world map and it is likely that new applications will eventually be released that make use of this feature.

Internet users who want to test the new geolocation feature need to download the latest version of the Google Chrome dev release to do so and start the browser with the parameter mentioned above.

It should also be noted that permissions are not persistent and that wifi based location is currently only supported on Windows and Mac (but not OSX 10.6).

A click on the Share Location button will share the current location with the website while a click on Don’t Share will prevent it.

To be precise, the following information will be send to the website:

Your computer’s IP address,
Information about the nearby wireless access points, and
A random client identifier, which is assigned by Google, that expires every 2 weeks.

Firefox users who never intend to use the geolocation feature might want to disable it permanently. This can be done easily by typing [about:config] in the Firefox address bar to open the Firefox configuration. The feature can now be disabled by entering [geo.enabled] into the Filter form at the top and pressing the enter key. The geo.enabled parameter should now be displayed. The easiest way to disable geolocation is to double-click the entry so that the Value displays false afterwards.

You find more information about geolocation on the Location-Aware browsing page over at Mozilla which also explains how to get remove permissions that have already been granted to websites and the random client identification number.

So, a very interesting question is how does such technology work?

They consult a service called Skyhook Wireless. They drive around settlements in several countries and record the GPS co-ordinates of where they pick up certain wireless access points, so when users send the access point’s MAC to them, it can return the co-ordinates. Many areas aren’t covered but if you would still like to use it, and let others use it, one can manually add details to the system. The same system is used to correct erroneous listings.

Many services already make use of WiFi-based location services.

For example, GPS units may struggle to provide an accurate location indoors or in an urban environment, but Skyhook Wireless doesn’t have this problem. Software like Google Maps on the iPhone use WiFi-based location in such scenarios.

Several online websites also use WiFi-based location services to return information based on the locality. Some are social networking, like brightkite and Fire Eagle to local search, although these services tend to be American. MyLoki is another service which relies on geolocation, and this allows location data to be exported to RSS feeds, Facebook or even Twitter. It can also grab data from ‘channels’ and plot things nearby on a map. These ‘channels’ include everything from Starbucks coffee shops to geotagged photos, Yelp reviews and cinemas.

Google Gears uses its own geolocation service, which websites like ITN use, but this is much worse than Geode/Skyhook, being accurate for me to about 150 miles instead of 15 meters!

Skyhook-based locations are built into the iPhone, the Opera web-browser and Mozilla Geode.

Privacy concerns are put to ease as data is only sent if you confirm the website can have access to it, and the software lets you specify how accurate a location you’re willing to send.

The idea of geolocation and WiFi positioning is fantastic. Eventually, it will allow you to open your laptop and then share your location with others, should you choose, or find the nearest restaurant in a distant city!

Only a few digital cameras support that the geolocation is automatically added to the Exif data of the picture, but don’t worry if your camera can’t do it automatically. Panorado Flyer makes it easy to edit the data and add the geolocation to the image. This is done by using Google Images to find the location that the image was taken and adding the coordinates found using the context menu.

I think that this is an excellent way to spice up those boring “we are back from holidays, take a look at all the pictures that we have taken” kind of events. This tool would be even nicer if it would be possible to create automatic slideshows showing the images and Google Earth locations and burn those information on a DVD to view on tv.