At its most basic level DAN allows you to add (and update) debts and assets in your wordpress admin area. DAN will keep a history of your updates that can help you to visualize your progress of either paying down debt or increasing your networth. Using widgets or the DAN API, you can also display your debts and assets in your wordpress front end for your visitors to see.
DAN also comes with a basic and advanced line graph (also available in widget or API form) that will display progress for one or more accounts.
API reference at:
http://www.savingadvice.com/tools/dan/extend/wordpress/