Social networkers are already used to being asked 'What's on your mind?' by Facebook and 'What's happening?' when it comes to Twitter.

However, that's getting old already.

The burning question for the next wave of social networking is 'Where are you?' - and services like Foursquare, Gowalla, Brightkite and Loopt want you to use your smartphone to answer it.

The technology at the heart of this trend is called geolocation; and with a GPS-enabled smartphone such as the Apple iPhone, Google Nexus One or RIM's BlackBerries, you can use it to let your friends know where you are, or to find places recommended by people you know, or to check in remotely at clubs, bars, and restaurants.

Regardless of privacy concerns (which I'll look at later in this article), it looks as though nothing will stop geolocation.

How it works

Typically, geolocation apps do two things: They report your location to other users, and they associate real-world locations (such as restaurants and events) to your location.

Geolocation apps that run on mobile devices provide a richer experience than those that run on desktop PCs because the relevant data you send and receive changes as your location changes.

Smartphones today have a GPS chip inside, and the chip uses satellite data to calculate your exact position (usually when you're outside and the sky is clear), which services such as Google Maps can then map.

When a GPS signal is unavailable, geolocation apps can use information from mobile towers to triangulate your approximate position, a method that isn't as accurate as GPS but is has greatly improved in recent years.

Some geolocation systems use GPS and mobile site triangulation (and in some instances, local Wi-Fi networks) in combination to zero in on the location of a device; this arrangement is called Assisted GPS (A-GPS).

As long as the sky is fairly clear, the geolocation app on your phone can ascertain your position reasonably accurately.
Indoors, however, it's less accurate, and in locales where storefronts are in very close proximity, you may have to select your location manually from within the app interface.

Eventually, though, more-advanced A-GPS systems should increase the accuracy of geolocation positioning inside buildings.

NEXT PAGE: The first wave of apps

  1. How it works, the apps you need and how your privacy will be affected
  2. The first wave of apps
  3. Google, Facebook and Twitter join the party
  4. Geolocation and your privacy