Even though, in social media, the term “sharing” is a multifaceted construct - influenced by user motivations, expectations, and social benefits to be gained - there are few definitions that approach it around these terms. We analyze these benefits in terms of what we call sociability affordances - i.e., social network site (SNS) affordances that arise outside either the merely material or imagined affordances - which enable individuals to take social actions toward social integration and interaction. Semi-structured interviews with young Chileans from three representative social media use typologies showed that each were closely linked with the performance of sharing actions for intrinsic and extrinsic social integration and interaction gains. Coding of interviews found four main sociability affordances from sharing practices: social visibility; audience engagement; social strengthening and enduring intra-personal communication. This study finds that online sharing behaviors are carefully weighed upon to achieve either factual or imagined social gains.