BackgroundThousands of health-related online discussion groups are active world-wide however, very little is known about the purpose and usefulness of such groups. In 2003 an online discussion group called ‘forensic occupational therapy’ was established in the United Kingdom. This group was examined to gain an understanding of the purpose and use of online discussion groups for health professionals who may be practically and geographically isolated from others in similar areas of practice.MethodsFollowing a case study design, descriptive characteristics on members’ locations and number of posts were collected from the forensic occupational therapy online discussion group. Eight years of posts (2003–2011) were examined using a theoretical thematic analysis process to identify and describe the purposes for which members were using the group.ResultsMembers from 20 countries contributed to the discussion group; the vast majority of posts being from members in the United Kingdom. Activity within the group was consistently high for the first five years however, activity within the group declined in the final three years. Six purposes for which members use the online discussion group were identified: seeking and giving advice, networking, requesting and sharing material resources, service development, defining the role of occupational therapists, and student learning.ConclusionsFindings suggest that health professionals in specialized and often isolated areas of practice are keen to connect with colleagues and learn from each other’s experiences. The main purposes for which the online discussion group was used could be summarized as communication, information sharing and networking; though activity within the group declined significantly during the last three years of the data collection period. This raises questions about the sustainability of online discussion groups within the rapidly developing social media environment.