A flash widget is a small application written in Adobe flash that is portable and can run on any web browser that supports the Adobe flash plugin, which is pretty much every single browser, minus most mobile browsers. The plugin can be downloaded for your browser here. The flash content can be placed on any website using a standard code format. When this code is place on a webpage the flash application will load and run on your webpage. A famous use of a flash widget is the video player in Youtube. This is why anyone can place a YouTube video on their own webpage. It can be summed up as a portable web application.