The amount of user-generated digital content in social media has exploded during recent years. Currently, it is easy to capture and produce versatile personal content, for example, activity data that is recorded with devices, such as heart rate monitors or the preference data of the music you listen to. A plethora of services exists for content sharing. Sharing digital content, such as images, audio, and video allows people to express themselves, create new contacts, strengthen ties with existing contacts, and to collaborate with other people. Social activities through content can create a sense of belonging and being part of a community. Digital content mediates social interaction through online services. For example, a shared video tells someone the story of an event that they could not be physically present at, and then shared exercise data might inform others of an interesting cycle route for a specific type of exercise. The sharing of traditional, personal digital content such as photos and videos has been widely studied, but recently it has become increasingly common to produce different types of content collaboratively and various services enable social interaction around such content – not just the sharing of it. The guidance for designers on how to build services to enable users to engage in these interactions naturally is still limited. To design better services, we need a better understanding of user activities together with the shared content and the collaborative practices that they form. Thus, this work focuses on novel types of user-generated digital content as well as the related activities, motivations, and user experiences.This compound thesis contributes to the research field of human-computer interaction; more specifically, the user experience. The thesis contains findings from six user case studies, involving a total of 328 participants. Through the case studies, we identified the elements that contribute to the user experience of content-mediated interaction with various content types. The theoretical contribution of this work is the introduction of the concept of contentmediated interaction. This work identifies the different elements that affect content-mediated interaction, and builds a content-mediated interaction model. The work extends the knowledge of user activities and the related user experience with novel types of shared content and of the user’s motivation to participate in content-mediated interaction. As a practical outcome, the thesis presents design implications. The thesis first proposes that understanding content-mediated interaction helps to design better applications and services that support online social interaction. Second, this helps to evaluate and refine the existing services as well as understand the emerging new content types in the future. Understanding the underlying activities and motivations supports the creation of new interaction features, service concepts, and finally, identifying business prospects
