Reporting spam/phish from Outlook via the plug-in only does that. It is packaging up the message and sending the message example off to our @access.ironport.com address for submission from that end-user. The plug-in itself is not actually doing any work to update the anti-spam on your appliance. These submissions are a work by themselves that is submitted and then reviewed from the rules writing process. In time, these submissions are scored, updated, and then written into the current IPAS (IronPort Anti-Spam) rules sets that are published back out to the ESA(s) themselves. So - as long as your ESA is set to get updates (by default, each 5 minutes), then you will get the updated rules --- and these rules are for everyone globally.
Hope that helps! If not - let me know.
-Robert