This document summarizes research on conducting group-based studies online using Facebook groups. Researchers recruited participants from rare disease communities on Facebook and conducted a 22-week asynchronous online study using a private Facebook group. Participants engaged in 11 discussion activities and researchers analyzed interactions. Key lessons learned included building rapport during recruitment, obtaining informed consent electronically, allowing socialization separate from activities, and being mindful of multiple data collection methods. The researchers propose iterating this approach with other populations and stages of design research.