Monitoring user activity

A method for monitoring user activity in respect of a plurality of applications on a computing device. The method comprises storing, by a first application running on the computing device, a first timestamp indicating the time that user activity was last detected with respect to the first application. The first application receives a message from a second application running on the computing device. The message comprises a second timestamp indicating the time that user activity was last detected with respect to the second application. The first application updates the first timestamp based on the second timestamp when the time indicated by the second timestamp is later than the time indicated by the first timestamp. Thus, user activity across the plurality of application can be monitored, such that an inactivity timer running on a particular application in the group of applications can account for user activity with respect to the other application in the plurality.