Spacetime Characterization of Real-Time Collaborative Editing

Real-Time Collaborative Editing (RTCE) is a popular way of instrumenting cooperative work on documents, in particular on the Web. Little is known in the literature yet about RTCE usage patterns in the real world. In this paper we study how a popular RTCE editor (Etherpad) is used in the wild, digging into the edit histories of a large collection of documents (about 14000 pads), retrieved from one of the most popular public instances of the platform, hosted by the Wikimedia Foundation.The pad analysis is supported by a novel conceptual model that allows to label edit operations as 'collaborative' or not depending on their distance - in edit position (space), edit time, or spacetime (both) - from edits made by other authors. The model is applied to classify all edits from the pad corpus. Classification results are further used to characterize the collaboration behavior of pad authors. Findings show that: (1) about half of the pads have a single author and hence witnessed no collaboration; (2) collaboration on common document parts happens often, but it happens asynchronously with authors taking turns in editing; and (3) simultaneous editing of common document parts happens very rarely. These findings help in revisiting early RTCE design decisions (e.g., the granularity of conflict management in RTCE protocols) and give insights on how to address novel needs (e.g., end-to-end encryption and offline editing).