This paper describes the Differential Synchronization (DS) method for keeping
documents synchronized. The key feature of DS is that it is simple and well suited
for use in both novel and existing state-based applications without requiring
application redesign. DS uses deltas to make efficient use of bandwidth, and is
fault-tolerant, allowing copies to converge in spite of occasional errors. We
consider practical implementation of DS and describe some techniques to improve its
performance in a browser environment.