15. The first computing device of claim 11 , the computer-readable instructions further causing the first computing device to: lock the first unit of data when the update is received from the second computing device.
11. A first computing device comprising: a processor; and a memory communicatively coupled to the processor, the memory storing computer-readable instructions that when executed by the processor cause the first computing device to: receive and display edits from a first user to a document displayed at the first computing device; concurrently receive an update from a second computing device, wherein the update includes one or more edits to a first unit of data of the document displayed at the first computing device; automatically apply the update to the document; and automatically provide an annotation for display on the document at a location associated with the first unit of data, the annotation identifying a name of the second user to indicate editing of the first unit of data by the second user.