It's currently not possible to batch reply to notes. Often, after reviews for instance, many shots will have the same reply to a note, like "Approved!". So instead of having to add this reply to many notes one-by-one, batch replying would be a great time saver.
What would be a great feature is either an addition to the Action Menu Item (upon right clicking) to "Reply to Selected Notes", or the ability to right click, "Edit Selected..." and then batch reply to multiple notes.
Click 'Me Too!' to vote up this feature, and add any additional thoughts or use cases in the comments.