This thesis followed the call for studies that intertwine behavioral science and
design science research within the Information Systems (IS) and Human Computer Interaction
(HCI) disciplines and consequently implied a broad range of qualitative and quantitative
methods. A brief review of IS, HCI, and social sciences research literature delineates related
work on online social networking and the scope of the underlying thesis. A series of exploratory
focus group and semi-structured interviews, and an explorative quantitative study in form
of an online survey (N = 102) were conducted in order to identify and better understand expectations,
needs, and concerns towards online social networking among the elderly. An extensive
literature review of relevant socio-psychological notions and an explorative
quantitative study (N = 109) on the formation of social connectedness on the SNS Facebook
supported me in theory building and the development of proposed measurement and structural
research models. Established hypotheses on cause-and-effect relationships between constructs
and corresponding measurement models were then tested by employing two surveys in the
form of online questionnaires distributed within the SNS Twitter (N = 121) and Facebook (N
= 147). Deduction of social design principles followed a theory-driven design approach. An
experimental methodology was chosen to evaluate selected social design principles with elderly
subjects that comprised of a laboratory experiment and quantitative evaluation based on
expectation-confirmation theory, and a longitudinal field test and confirmatory focus group
interviews (N = 51).