Modify bulk_views edit user message
Use the string overrides module - anything passed through t() will be caught by this and it provides an admin interface similar to the localization functionality to make it easy to look up these strings and translate or change them as you like. It also recognizes variables so you can still use the context of the function. From the module:


  
  Easily replace anything that's passed through t()
  Locale support, allowing you to override strings in any language
  ...
  Note that this is not a replacement to Locale as having thousands of overrides 
  can cause more pain then benefit. Use this only if you need a few easy text 
  changes.
  


You can also do this in your settings.php file with a simple array, ex:

$conf['locale_custom_strings_en'][''] = array(
   'Performed %operation on @items.'      =&gt; 'Your Changes',
);


This handbook page covers both of these methods in much more detail.