I seem to get asked this question a lot…what is the difference between a plugin and a widget? 

PLUGIN: 

A WORDPRESS PLUGIN is a program, or a set of one or more functions, written in the PHP scripting language, that adds a specific set of features or services to the WordPress weblog, which can be seamlessly integrated with the weblog using access points and methods provided by the WordPress Plugin Application Program Interface (API).

Plugins can extend WordPress to do almost anything you can imagine. In the directory you can find, download, rate, and comment on all the best plugins the WordPress community has to offer. [hr]

WIDGET: 

Noun
  1. A small gadget or mechanical device.
  2. An application, or a component of an interface, that enables a user to perform a function or access a service.

WORDPRESS WIDGETS are a great way to bring in extra bits of functionality to your website/blog, and as with much everything else in WordPress, they’re surprisingly easy to manage. So, what exactly is a widget? 

A widget is a little object that sits inside a special area of your theme design and has a dedicated purpose, for example, adding functionality, information or navigation.   Different widgets might offer a Twitter feed, a calendar for displaying posts by date, a tag cloud or an external RSS feed.   Different widgets can be added to widget areas, which are set  up by the theme author.   Just like the primary navigation of your site, setting up widgets to suit your needs, content and visitors will help make your blog unique and personalized.

A personalized widget can give your readers extra information relevant to your subject to keep them on your page that little bit long, and with the ability to link in functionality with social networking, make your site a handy hub of web-based activity.    Let’s look at a live demonstration.