What's the distinction between a dialog and a design dialog?

Dialogs & Design Dialogs are the group of widgets employed to obtain input from the author. These are the most important parts of a component since they allow the author to communicate with the CQ5 component. It indicates that values entered by the author in these dialogs are used as input for a CQ5 component.

Criteria Dialog Design Dialog
Definition Dialog modifies the content at the page level. Design dialog modifies the content at the template level.
Availability authored in edit mode authored in design mode
Value Storage stored under the pages jcr:content node stored under the design page located under /etc/design
Accessing Values in CQ5 JSPs through properties object through currentStyle object.