As an application's complexity increases, it becomes harder for the user to find what they need. To accommodate the complexity of a user interface, it is common to separate the data or options into groupings. The concept of Progressive Disclosure shows the needed information as necessary. Progressive Disclosure may be user-initiated, system initiated, or a hybrid of the two.
Examples here include a Show More button for launching a child dialog, Tabs for chunking interface elements into logical chunks, and a Collection Search/ Filter for selectively displaying items in a collection by certain criteria.
These can either be:
Event based: An event within the product initiates the disclosure of more information, such as with a Task Dialog.
Time based: More information is disclosed after specified amount of time passes, such as in an automatic slide show.
An example of a hybrid is Progressive Tooltips, where the user initiates the initial tooltip by hovering the mouse over the control, but after a set amount of time a more detailed tooltip appears.