9. The method of claim 1 , wherein at least a portion of the plurality of activity data items of the hierarchical data structure include a start date; and wherein the method further comprises refraining from displaying an activity data item having a start date prior to the start date thereof.
1. A method comprising: storing, in a first area of a memory of a first computer system, a hierarchical data structure including a plurality of activity data items each representing an activity and each having a description and a status, wherein: each activity data item other than a root activity data item is a child of a parent activity data item and represents a subtask of the task represented by the parent activity data item; and the status for each node is recorded in a data field associated with that node; storing, in a second area of the memory of the first computer system, an unstructured set of activity data items each having a description; receiving a user input instructing a processor of the first computer system to associate an activity data item from the unstructured set of activity data items with the hierarchical data structure as a child or parent of one of the activity data items of the hierarchical data structure; receiving from a second computer system an additional activity data item; and storing the received additional activity data item in the second area.