Learning takes place in a social context, shaping and shaped by discourses. In online projects such as the Schome Park Programme, these discourses are semiotic practices that make use of writing and other manifestations of digital literacies. Discourses include traceable patterns with linguistic features of distinctive forms and functions. They are also shaped by the affective concerns of those working and playing with them in context. Online, two primary types of learning context have been identified: networks and communities. While networks may offer a wealth of people and resources, communities appear to offer richer learning possi-bilities. It is therefore important to investigate how online learning communities can be formed through online networks, and how discourses as mediated actions arise from differing expectations, misunderstandings and even conflicts. The study reported here focuses on two groups of teenagers, one a formal learning community based in the USA joining a larger, online, informal learning community based in the UK. The groups were originally only weakly tied within a network, but aimed to create a single learning community through activity in an online forum, wiki and virtual world. Thematic analysis of forum posts shows the importance of cohesive ties – grammatical devices used to construct coherent narratives – to the development of key elements of community: spirit, authority, trade and art.