Chapter 7: Application Outlook 295 Consider a camera phone equipped with a GPS receiver or an equivalent positioning technique. An obvious application is a photo album, which stores the images and includes location information in 11 each photo. This is exactly what Nokia Album does. The photos can be grouped based on location; furthermore, location can be used as a search term. Many studies exist on augmenting photos with location information (Davis et al. 2004; Toyama et al. 2003; Sarvas et al. 2004; Naaman et al. 2004). Obviously, photos are not the only content type that benefi ts from the inclusion of location metadata. In fact, any piece of content would benefi t if location information was included. Consider, for instance, editing a text document. Each time you modify it, the fi le system auto- matically stores a timestamp along with the fi le, so you are able to see when the fi le was last modifi ed. Why not include location information in a similar manner? It would then be an inherent characteristic of any piece of content, and as accessible as the timestamp is today. In essence, such information would be extremely useful in searching, even though the content itself might have no relation to the location that was created or last modifi ed. 7.2.5 Location and Communities The ability to access another user’s current location, either continu- ously or by defi ned intervals, is referred to as tracking. Tracking allows many social applications, such as group communication and planning, and location-aware presence – that is, the ability to check a friend’s current social status, including availability and location (Lehikoinen and Kaikkonen 2006). In essence, social location information can be divided into two categories: 1. Where’s everybody? 2. Is anybody there? Tracking the location of other people is a strong candidate for making location-aware applications a wild success. Combining the features discussed in the preceding sections, such as the creation and sharing of POIs, one can effortlessly envisage concepts that allow creating personalized maps, sharing them with friends, and, by including track- ing the location of the group members (dynamic POIs), ad hoc plan- ning. The options are indeed numerous. 11 http://europe.nokia.com/nokia/0,6771,58681,00.html