Future ideas: use HTML5 storage to allow users to create/modify their own messages.
- double click on a title or description to modify
- save/cancel
- 'reset' link at bottom of popup (not shown above) resets all custom messages to default
Important
- The 'Welcome to SiteName!' text is prepended automatically if the user has been member for less than a week.
- This uses HTML5 Storage, so custom texts only work on the site where they were entered.
NOTE
With this modification, there is no longer any reason that this userscript should be strictly limited to 'review'. I may end up editing the question appropriately.