Online technologies are promising for helping older adults maintain social connectedness, particularly with younger people, yet many older adults resist or participate minimally in the mainstream technologies used by younger members of their social network. We present results from an interview study involving 22 older adults (age 71-92) to understand communication preferences and values related to social media. Seniors articulate many concerns with online social media, including the time required for legitimate participation, the loss of deeper communication, content irrelevance, and privacy. Additionally, older adults engage in social practices that could be supported by online social technologies, but they rarely use such tools. The theme of material social communications emerges from our data, and we examine this in context of online social media. We conclude with design considerations for the development of social media for older adults, and as part of this we describe the notion of bridging technologies as a framework for intergenerational communication design.