One of Joomla's main weaknesses is it's lack of content categorization. The default core of Joomla allows administrators to define sections, section categories, and category content, which limits Joomla's depth of categorization.
Deep pockets II allows administrators to build a nested category structure that can be linked to any content items, and also includes a sub-template system. The sub-template system creates the option to customize the look of each individual category.
You can find out more about Deep Pockets II here.
The release of this component is very exciting news for the Joomla community. Often, potential users of Joomla are turned off by it's lack of content organization for information driven websites. Now, though in beta stage still, Deep Pockets II opens the door for content categorization in Joomla.