A "widget" is an application that sits on top of a Web site and offers users additional interactive features. There are thousands of kinds of widgets! Popular widgets (Google calls them "gadgets") include photo slide shows, videos, music playlists, post-it notes, horoscopes, and virtual pets that can be fed and dressed. Widgets are normally added to social networking profiles, blogs, or Web sites.
The main types are (1) a widget engine (such as dashboard apps like Apple's Mac OS X v10.4, Windows Vista Sidebar, or Yahoo! Widgets), (2) GUI widgets (which are a component of a graphical user interface in which the user interacts), (3) Web widgets (which refer to a third party item that can be embedded in a Web page), and (4) mobile widgets (a third party item that can be embedded in a mobile phone).
In some cases, widgets are created and customized on another site (such as Slide or Photobucket). The site generates a string of software code to be copied and pasted onto your page. Some social networking sites and widgets are becoming more closely integrated, requiring only a click of a button that tells the two Web sites to work together (see also: API).
Technically speaking, in the traditional sense a "widget" is a placeholder name for an object or a manufactured device. On the Internet, a widget refers to an interface element that a computer user interacts with, such as a window or a text box. As opposed to a physical widget in the real world, Internet widgets are virtual in the sense that they have virtual buttons that can be clicked with a mouse cursor (versus physical buttons that can be pressed with a finger). Widgets are usually packaged together in widget toolkits, and can be used on several Web sites.