1This paper will present the concepts behind the Textual Communities system, a new collaborative environment for the making of online scholarly editions. Textual Communities differs from all other systems for online editing in multiple respects. Firstly, it is built on explicit recognition that textual documents must be represented according to two distinct hierarchies: that of the document (book/page/column/line) and that of the communicative acts inscribed in the documents (poem/stanza/line; volume/chapter/paragraph). Secondly, Textual Communities builds each hierarchy on the basis of an explicit ontology linking together the textual scholarship fundamentals of document, act of communication (“work” in textual scholarship) and text (defined as an instance of an act of communication in a document). Thirdly, the new version of Textual Communities implements these concepts in the form of a JSON document database (mongoDB), optimized for online real-time collaboration. Further, Textual Communities embodies a vision of scholarly editions not as the product of discrete scholarly endeavours (whether by individual scholars, or groups led by scholars) but as community efforts, where work and the products of the work are distributed freely across the communities which make and use the base materials of scholarly editions: transcripts, images, collations and analyses. Thus, it includes an API designed to facilitate re-use and extension of all materials created within Textual Communities, with the aim that editions and their component parts may interlock with other materials and other editions across the web. The paper will show briefly some of the features of the system, by way of illustration, but its focus will be on the ideas behind Textual Communities. The current development instantiation of Textual Communities may be seen at https://textcomtest.usask.ca; the previous production version is at www.textualcommunities.usask.ca.