This paper examines the type of creativity involved in the humorous exchanges that pervade an online discussion board where all interaction and relationships between participants are textually co-constructed. Taking a view of creativity as context-dependent, it considers how participants exploit the particular features of an online environment in which different discussion threads compete for attention, choreographing their contributions to be appropriate both to the evolving context and to the social practices of the group. It argues that wordplay in this environment contributes to a dense textual cohesion that helps to keep topics "in play." This textual cohesion, like the humour, is jointly constructed, and both reflects and helps to constitute the social cohesion of the group.