Google calls it Gadgets and Yahoo calls it Widgets. Call it anyway, Gadgets and Widgets for the web have been a great help to web publishers who can easily integrate thematic gadgets/widgets into websites/blogs to provide interactivity and stickiness.

http://www.widgetbox.com/
http://www.google.com/ig/directory?synd=open

Gadgets/Widgets are available for desktop too! I am for the web and exploring new ways of integrating gadgets/widgets into new ideas!