This plugin allows assigning a shortcode to any widget so that it can be inserted anywhere (provided the element supports shortcodes).

It’s a plugin I use on many sites.

There are two ways to create such a reusable widget:

1. Add a widget to a widget area as usual. With the plugin activated, every widget is automatically assigned a shortcode. Also, any widget created prior to activating the plugin will be assigned a shortcode.
2. Add a widget directly to the “widgets for shortcode” sidebar. This is useful if you have some content you want to reuse inside of pages or posts but do NOT want it to appear in a widget area. For example, you could create a Text or Custom HTML widget here that displays an affiliate disclaimer. Then you could add the shortcode to any post which reviews or recommends a product or service for which you are an affiliate.

Here’s a normal widget in a widget area, with the shortcode displayed:

And here’s a Custom HTML widget that resides only in the “Widgets for Shortcodes” widget area. Its purpose is to display that affiliate disclaimer I mentioned in the example above.

And now here is the code for entering the affiliate disclaimer, followed by the actual disclaimer:

[do_widget id=custom_html-2]