Due to the increasing Internet usage of elderly people, Social Network Sites (SNSs) for this audience group gain in importance. The present study analyzed 19 Germanspeaking online platforms for the elderly with regard to 26 specified success criteria. Therefore, a subjective evaluation on the basis of those criteria was conducted for social community, forum and content management system as most important types within SNSs. In order to approve this evaluation, objective data was gathered from providers of third-party website analyses. On the basis of a group discussion and an additionally matrix analysis, the study showed that website's success does not depend on the quantity of offered main categories but rather on mature and distinct functional offers. Within the matrix analysis, a large variance (41.8 vs. 6.0) between the analyzed SNSs was highlighted. Within this important audience group, achieving a critical mass is a major prerequisite