The only WordPress plugin not afraid to give you dirty looks.
The purpose of this plugin is to shame content editors into updating page content that has not been touched in a long time, while simultaneously providing an overview of the oldest pages on a site. Also: gifs.
The plugin adds an Out of Date Pages subpage under the Pages menu, which breaks all the pages on the site down by last modified date, grouped by years since it's been modified. Each page listed has a link to edit the page. All images on the Out of Date Pages subpage are sourced from reactiongifs.com.