What is a widget?
It's a small application that can be installed within a web page or blog by reusing specific code behind the scenes in the HTML section to make the visual display look neat and uniform as well as interactive. Widgets can be used to allow people to subscribe to newsletters, like Facebook pages, display the latest tweets from a twitter page, and more.
What Are a Few Examples of Widgets?
The HTML for my Facebook looks like:
This is what the code above looks like when inserted properly on the HTML page: