UpdatePatrol (formerly DeltaSpy) enables you to check your favorite sites or blogs for updates and view the highlighted changes from a built-in browser preview. The program works silently in the background and notifies you from the system tray when changes were found. You can configure each site individually and also set specific criteria with keywords and Regular Expressions. Other features include support for HTTP authentication, easy addition on new sites via drop target, user-defined categories and more. DeltaSpy supports monitoring of ordinary web pages as well as RSS, Atom, RDF, XML and text files on the Internet.