Posts/Pages

If u make use of a page/post cache system like Quick Cache you can have this plugin monitor the cache files..any changes that appear will let you know (assuming you turn off date changes). Some times these cache type plugins may add a footer indicating the cahce was updated..that would need to be turned off or u will get false positives.

Besides that you would need to write a plugin that could routinely check your posts in the dbase. It’s quite simple to do — even now i have thought up the code in my head.