Yahoo! Widget Engine (formally known as Konfabulator) is a JavaScript runtime engine for Windows and Mac OS X that lets you run little files called Widgets that can do pretty much whatever you want them to. Widgets can be alarm clocks, calculators, can tell you your WiFi signal strength, will fetch the latest stock quotes for your preferred symbols, and even give your current local weather. What sets this apart from other scripting applications is that it takes full advantage of todays advanced graphics. This allows Widgets to blend fluidly into your desktop without the constraints of traditional window borders. Toss in some sliding and fading, and these little guys are right at home in Windows XP and Mac OS X.

       
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Use widgets to enhance your destop with usefully small applications. Has quick shortcut to Yahoo search box,hotkey for heads up display,auto hide or play sounds for dock,set proxy settings and language.More than 1000 widgets are available from the producer. Can join Yahoo! Photos directly,using your email account.See weather in your desired city.View Nasdaq evolution.
You can create your own widgets and a manual for help can be read on developer site.Search them from the internet.