This article is derived from a study of the use of Facebook as an educational resource by five dyslexic students at a sixth form college in north-west England. Through a project in which teacher-researcher and student-participants co-constructed a group Facebook page about the students' scaffolded research into dyslexia, the study examined the educational affordances of a digitally mediated social network. An innovative, flexible, experiential methodology combining action research and case study with an ethnographic approach was devised. This enabled the use of multiple mixed methods, capturing much of the rich complexity of the students' online and offline interactions with each other and with digital media as they contributed to the group and co-constructed their group Facebook page. Social perspectives on dyslexia and multiliteracies were used to help interpret the students' engagement with the social network and thereby deduce its educational potential. The research concludes that as a digitally mediated social network, Facebook engages the students in active, critical learning about and through literacies in a rich and complex semiotic domain. Offline dialogue plays a crucial role. This learning is reciprocally shaped by the students' developing identities as both dyslexic students and able learners. The findings suggest that social media can have advantageous applications for literacy learning in the classroom. In prompting learning yet remaining unchanged by it, Facebook can be likened to a catalyst.