This work studies the experiences, challenges, and strategies of people with dyslexia when using social media. We interviewed 11 people with dyslexia to understand their general experiences with reading and writing content on Facebook. The interview study findings highlight the challenges they face when writing content on Social Networking Sites (SNSs), and their strategies for mitigating these challenges. Following up on this, we surveyed 492 participants, among whom 67 self-reported as having dyslexia. The survey results confirm challenges with and strategies for writing unique to people with dyslexia, although they also suggest that better writing support on SNSs may be more broadly beneficial.