248 Personal Content Experience: Managing Digital Life in the Mobile Age practices and conventions used in the platform. The guidelines, if used properly, support learning and understanding on how the system can be used, as they aid in creating a consistent design. Also standards, such as the ISO 9241 series, offer guidance by providing information, requirements, and recommendations related to certain hardware or software (ISO 1998). After sorting out the technical issues, the design continues. In order to guide the design for the UI structure and component specifi cation, the designer should consider the following questions and try to answer them during different phases of the design (Aaltonen 2007). What content should be presented? This fi rst question is fundamental, since it sets the boundaries for all subsequent questions. The answer depends on several factors, such as the current context, current user task, previous states of the UI, user preferences, and device capabili- ties. The amount and type(s) of content should be defi ned, because this will set the frames for the other questions. How to present the chosen content? After knowing what is going to be presented, we can select a suitable presentation method. The previous system state, selected content, system hardware and software capabili- ties, and user preferences, etc., have an effect on the presentation. Furthermore, presentation and interaction, addressed below, are heavily interlinked. To defi ne a presentation technique, we should fi rst select the output modality, such as speech or visual. The modality used in the previous state should usually remain, because it makes no sense to switch modalities frequently. Then again, synthesized speech is troublesome for presenting dozens of images, as the output modality does not support the content modality. Alternatively, speech is fi ne for synthesizing the contents of a text message. The presentation technique depends on content type, but we need to consider what information is shown for each object (what metadata attributes and their values are presented and so forth) and how the information is presented: as text, graphics, or audio. If the visual pre- sentation is used, the screen resolution, orientation, and size affect the layout to a great extent. How to interact with the content objects and information? The objects and presentation guide interaction, which depends on the previous system state and selected objects, as well as system hardware and soft- ware capabilities, user preferences, and so on. The presentation tech- nique is tightly linked with the input capabilities of the device, because the presentation should be such that the user can interact with it. Also, the interaction occurs on several levels – with the highlighted object,