Or alternatively, the number of bugs reported against each source file. Or the number of uncommented methods in each source file. Notifications users can subscribe to be notified of changes in certain objects. Notification messages can be accumulated and sent in batches to a given user as a digest. Depenencies keep track of which other object need to be updated once the given object is modified.
Subscriptions allow users to specify the notifications that they want.
Users can also subscribe to an object. For example, subscribing to a FAQ with a period of once a week would give a user an email with the complete FAQ once a week. Data entry page is used to enter new questions or answers. Users may vote on questions that they would most like to see anwered. Users may rate answers.