Patent attributes
Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, include sending a first electronic document to a first client device over a data network from a web server. The first electronic document includes multiple document elements formatted according to a first document schema for a first client application. The document elements include multiple content elements and one or more presence elements. Presence data is received over the data network at the web server from the first client device. The presence data includes an identification of one or more of the content elements of the first electronic document. The presence data also includes an identification of a status of the first electronic document for the first client device. An updated presence element for the first electronic document, which includes a first presence object, is stored. The first presence object includes the presence data received from the first client device and an identification of the first client device and/or a first user associated with the first client device. The first presence object is sent over the data network from the web server to a second client device.
