WP Random Post Dater is a WordPress plugin that will randomly re-date your existing posts. So if you post 20 posts today but then decide you want to randomly space them out (either in the past, or for the future) then this plugin will do that for you.
Demo video
Here is a demo video of setting the date on 8 posts, randomly, from any time in the last 365 days.
Download
Right click and save this file to your computer then upload to /wp-content/plugins/ folder in your WordPress blog installation.
OR DOWNLOAD FROM WORDPRESS.COM : http://wordpress.org/extend/plugins/wp-random-post-dater/
How to install
Download the file and upload to your /wp-content/plugins/ folder. Then go to your Plugins section of your wordpress admin panel (http://yoursite.com/wp-admin/plugins.php) and activate it.
Once activated then under WordPress settings select ‘Random Post Dater’ (http://yoursite.com/wp-admin/options-general.php?page=random-post-dater).
Other Links
Feedback
Unfortunately I couldn’t reply to him (email bounced) and there is no way to undo the action of randomly changing the dates.)