62 Personal Content Experience: Managing Digital Life in the Mobile Age belong in a collection (be it a CD or a playlist); messages are necessarily related to at least contact information, and so forth. By automatically discovering relations between content objects, the user is not only able to see the larger picture they belong to, but also gain some understand- ing of their meaning. Finding and maintaining relations can be useful in several ways. Relations are a strong tool to facilitate searching. Should the system have some understanding of the semantic relationships between the content items, searches by example, for instance, may be greatly enhanced. Second, analyzing relations and presenting relations to the user unexpectedly may provide pleasant surprises and strengthen the wow effect: “How did my device know THAT?” (section 3.3.3). Rela- tions can be considered the glue that bonds the pieces of personal content together and provides meaning to them. The true power of relations, however, is not evident until they cross the content type boundaries and tie together all content objects that have a common character. Then we can start enjoying and re-living experiences, instead of just single content objects. What are particularly important are relations between content objects and people. Since it is personal content we are dealing with, the ability to link our digital memories with our social network plays a central role. Relations between content objects and people further contribute to the community aspect of personal content. 3.3.7 Privacy and Security Requirements Usually there are different privacy requirements for personal content. As discussed above, some pieces of content you may wish to keep for your eyes only, whereas some you may wish to share with your family or friends. In this case, the access is still restricted, as many different sub-levels or groups may need to be defi ned. Further on, some pieces of content may be public, so that anyone can access them. Another aspect to consider is that privacy defi nitions given for a certain piece of content may change over the course of time. Personal content still concerns us all. As more of our personal stuff – pieces of our life – become digital, more and more computer- illiterate users begin to use personal content management systems. It is of utmost importance to being able to secure the personal content, without any domain-specifi c skills, so that the general public do not have to worry about whether their contents are currently being stolen or abused, or that people who are unaware of such threats, can remain doing so without catastrophic results.