Responding to recent calls to transcend social media platforms when examining media effects, and using the social information
processing model to predict and explain results, this multi-method study first uses a US national survey (N = 325) to examine
perceived effectiveness of social support and relational closeness via paralinguistic digital affordances (PDAs; e.g., “Likes,”
“+1s,” and “Upvotes”)—the one-click tools for phatic communication—between social media platforms. Results of the
survey reveal some significant between-platform differences in perceived effectiveness of social support provided by a PDA,
but no significant differences in the relational closeness of ties across platforms. These findings were used to design and
conduct focus groups (N = 36) to understand why the identified differences exist. Focus groups reveal that although social
support is exchanged across all platforms, different dimensions of social support are sought and received depending on the
platform and the network audience that platform accesses. In addition, the focus groups revealed meaningful differences in
the nature of network relationships between the platforms, if not the degree of closeness. Taking the two studies together,
it seems the adoption and continued use of a platform is an idiosyncratic function of both the social and the technological.
Findings underscore the importance of conducting cross-platform studies and demonstrate the value of using PDAs as a
convenient cross-platform comparison tool, as they are one of the few common features across social media.