If you thought Twitter was just for ranting about how annoying the person sat behind you on the bus is, then think again. One of the most interesting ways you can use Twitter is to share details of exactly where you are with all your followers - and find out where they are to boot.
Trak is a free Android Twitter client that includes the functionality for sharing your GPS location. As a Twitter client, it's simple to use but very basic in terms of functionality. Once signed in, your Twitter feed will be displayed clearly in a scrollable window. You can tweet just by typing into the entry box at the top and clicking 'Twit this'. You can change the refresh rate using the options in the setup. Unfortunately, Trak doesn't allow you to open tweets and reply to them, search tweets or upload photos, etc.
Instead of providing all these standard Twitter features, the developer has concentrated on furnishing Trak with the ability to beam details of your location to the World. You can enter your current GPS location then share it on Twitter using the 'Zap GPS position' option. Your followers will then be receive a tweet with a link to a map of your current location, powered by Yahoo! Maps.
Likewise, you can also use Trak to find out the geolocation of your buddies. Simple click 'Where is...' and select one of your friends to view a map of their current location (provided they have a GPS service installed).
It's worth pointing out that, at present, Trak does not include a function for automatically retrieving GPS data from your phone. This is quite a major drawback considering that geotagging is the main purpose of Trak.
Despite its lack of Twitter features, Trak offers an interesting way to share your location via your phone.