There Can Be Only One

This plugin ensures that there is only one sticky post published to the site. When a new sticky post is published, previous the ‘sticky’ flag is removed from any other posts, so they will no longer appear at the top of your page.

Important Notes

• I adapted code initially found at http://craiget.com/one-sticky-post-in-wordpress/ Thanks to Craige for posting it! Also, Devin Price (http://wptheming.com/) was immensely helpful as I knocked out a couple of issues regarding scheduled sticky posts.
• The first time you publish a sticky post after enabling this plugin, any and all other sticky posts will be changed to not-sticky. There is not a way to automatically reverse this decision, nor is their a log of which posts were changed.
• This plugin has not been tested with versions of WordPress prior to 4.0.
• Do not use this plugin if you are using another to manage per-category sticky posts. It has not been tested with that setup, and it will most likely mark all of those posts as non-sticky.