A familiar internet concept

If you've ever used an instant messaging program on the Internet, you've probably noticed that you can set your status to "Away" or "At Lunch" or by entering your own message. This is the kind of info you'll see when browsing your phone contacts if you and your friends and colleagues are using presence. To make it a little more "you," just add an image and a nickname to your presence data and voilà: you have a mobile online persona. (Sharp and straight-laced or a creative manifestation of your inner self, how you make your first impression is up to you.) The main difference between Internet instant messaging and mobile presence is that you are frequently away from your computer, but you'll have your phone with you most, if not all, of the time.

Servers and subscribers

When you update your presence information, it's sent to and managed by the Nokia Presence Server. The Presence Server then sends out updates to anyone who subscribes to your presence info (not just anyone can subscribe - they need your approval first), or releases the data to approved contacts who conduct a one-time fetch of your presence status. This is, of course, done over a network connection such as GPRS, EDGE or WCDMA.

Choose what, when and to whom you show

If you use presence, you will have control over what information is given out and to whom. You can also show one message to your close contacts, another message to acquaintances, and yet another to strangers. When someone wants to subscribe to receive instant updates of your info, you can accept or refuse their request.

Compatible devices

Nokia now offers handsets that have the presence service already built in. This makes using presence a bit nicer as the developers can make use of that phone's other functions and richer graphics. If your phone does not have a built-in presence service but can connect to a data network (GPRS, for example), you may not have to be left out: try downloading a presence application.