This article is about the informal learning that took place in an online divorce support and advice forum. In it, the author discusses the formation of a community of practice among the members during the first nine months of the site's operation. The author shows how the key markers of mutual engagement, joint enterprise and shared repertoire developed between members, and argues that the community of practice both enhanced and inhibited learning among its members. In particular, the author suggests that members learned not only the knowledge about divorce law provided by others on the site as a form of public good, but they also learned ways of coping with divorce, with their ex-spouse and with the legal system generally. At the same time, however, some group practices inhibited learning, both for those participating in the community and for those excluded by members. The author concludes with suggestions for developing similar online communities of practice. (Contains 2 notes.)