WordPress introduced Post Revisions in version 2.6 which results in lots of posts (each revision) getting stored in the database. The feature is nothing I need or use and after seeing the result in my database size I looked for ways to disable it.
In How To Turn Off Post Revision In WordPress 2.6 is the answer to how to disable. To turn it off, add the following code to wp-config.php:
define('WP_POST_REVISIONS', false);
How to Delete Existing WordPress Post Revisions Stored/Saved shows how you remove existing revision posts from your database.
umm… where exactly in wp-config.php does this code go? apologies for the probably veru silly question?
You can place the code almost anywhere. I did add it after the last MySQL setting.