Chapter 3: Mobile Personal Content Uncovered 65 Likewise, contact information is content that is available to most e-mail clients. The way contact information is treated with mobile devices, especially mobile phones, is much more fundamental though: one could argue that in many cases, the user’s whole social life is rep- resented by the phonebook in their mobile phone. Furthermore, the contacts are generally considered the most valuable information in mobile phones. This suggests that the importance of a traditional content type, contact, has signifi cantly increased when it is used daily and relied heavily upon in most daily mediated communications. 3.4.4 Totally New Content Types, or Extended Use of Existing Content Types Mobility and the related use patterns brings along new kinds of infor- mation, which results in two issues dealing with content types: either new use patterns require totally new fi le formats, or existing fi le formats are modifi ed towards better fi lling the needs implied by mobility. Nevertheless, the trend contributes to the ever-increasing amount of content and variety of content types. The most characterizing aspect of mobility is, by defi nition, dynamic location. Mobile use is not tied to a certain location. The device can be, at least in theory, accessed anytime, anywhere. It is always with the user. These characteristics not only change our usage patterns (discussed in section 6.2 in more detail) but also reveal new forms of content altogether. Since the location of the user and their personal devices is not fi xed, information related to current context, such as location, is an obvious example of the content that has not existed on a stationary PC, where the location remains more or less static. This is with the exception of laptops and other portable computers, as these devices are not very useable while on the move. See section 2.1 for further discussion on static, nomadic, and mobile use situations. Personalized location-dependent information is typical of mobile use only. Such content includes your own location, the location of your friends, location-dependent personal reminders, and location-based services, such as advertisements. Applications that deal with location- based personal content are discussed in section 7.2. Another example is presence (or availability) information, which is traditionally used in instant messaging applications (International Society for Presence Research 2006). In traditional PC environments, a presence indicator and its associated text merely conveys whether you are available at your PC, busy working, or away from your PC.