Techniques are described for creating and modifying task records and for controlling information displayed to a user in corresponding task representations. The task records are associated with more or more user activities, where each activity is associated with a record having an identifier for the activity, an application identifier that indicates a software application associated with the activity, and a content identifier identifying content associated with the software application and the activity. The activity records can include activation information. A user can select a task representation and resume one or more activities associated with the task. Tasks records can be shared between different computer devices of the user, and with different users. Task and activity records can be associated with navigational mnemonics. Representations of task and activity records can be displayed proximate representations of associated navigational mnemonics to help a user locate tasks and activities of interest.