A widget is an application that can be integrated into a website or blog. Where the widget performs some database driven action on or provides information displayed within the widget. You might download a weather widget, and select your geographic location and put the weather widget on your blog with your local weather. Or you may simply display static information in the widget as it is embedded into a website.
I created a widget that features all of the Fellows who have written books in the Society of New Communications Research, I’m a Fellow and book author.
Many open source (free) and commercially available blogging systems provide simple mechanisms for blog owners to integrated widgets into their blogs. Rather than needing to know how to place html code into a blog, platform providers have built marketplaces for widget makers to promote their widgets across a blogging community; I wrote a post about some of the widget and plugin marketplaces available where website owners can find widgets or widget developers can promote their widgets once integrated into a blogging or website platform.
Widgets give the website owner a convenient way to gain access to data from other companies and organizations. The website owner has content that is relevant to their site, and the widget owner gets to provide their content and data across many different websites online.