1. A method at a computing device comprising: rendering a document at a display device using output of a document reading and/or writing application which is executing on the computing device or at a remote computing entity in communication with the computing device; receiving sensor data from one or more sensors monitoring user annotation events associated with the rendered document, whilst also, monitoring state data of the document reading and/or writing application; recognising one or more gestures by analysing the received sensor data; storing the state data with associated timestamps; storing the recognized gestures with associated timestamps; and calculating and storing a compressed record of the sensor data on the basis of the recognised gestures, the state data, and the timestamps.