This plugin enables you to edit and display Content Blocks in a sidebar widget or using a shortcode. Custom Post Widget documentation page.
Very versatile - use anywhere you need a bit of content to be repeated on several pages.
On InsideLaw, the Student and Faculty quick links boxes are built as a Content Block that can then be embedded in the home page and the respective landing page. These boxes can also be reused as left nav menus, if needed (see the Technology landing page for an example of the same Content Block in the main content area and as a left nav widget).
To control where the widgets containing Content Blocks are shown, we use the Dynamic Widgets plugin (more about InsideLaw Widgets).
If a Content Block widget shows up in unwanted places, it may be due to a conflict with another plugin. Checking the "Do not apply content filters" in the widget option usually fixes the problem. This is may be (?) only possible if the content block does not include shortcodes.
Content Block can also be inserted into the main content of page with the "[content_block]" shortcode via the "Add Content Block" button above the editor.