For customers who wish to invoke watermarking powered by Box right from the email experience, this is also possible with a Box and mxHERO deployment.  Here's a <1 min snapshot example of this:

https://mxhero.app.box.com/s/jlq1m6lqf2ozc8tfth2cxx6s4xa5b10v

On the specific question of gaining insights as to when someone has opened up a watermarked document, in addition to Box's capabilities - if a customer has mxHERO w/Box deployed, they can elect to receive notifications when ANY email w/attachment they've sent is opened regardless of file type.  This is because we extend Box's powerful capabilities to the email experience (including Shield) and here's an example of that 'tracking notification' a sender can elect to receive when someone they sent a watermarked file opens it up.  The sender will know when, where, on what device, etc their file was opened - a powerful collaboration and security win:

https://mxhero.app.box.com/s/x9ov9gcdu8e1ror3oe9bw2uik7ht0uem

Tracking Notes:

• 
  

  mxHERO has options to track only email attachments or email body opens & attachments

  
  


• 
  

  mxHERO uses a "tracking pixel" (industry standard approach) to capture email opening events

  
  


• 
  

  mxHERO attachment tracking is guaranteed since the recipient has to click through the link to get the file. This is superior to standard read receipts.

  
  


• 
  

  Tracking uses geo-IP to determine approximate location

  
  


• 
  

  mxHERO tracks each recipient and file separately. So the sender has a granular vision for each file by recipient.

  
  


• 
  

  mxHERO can be set up to always track on certain flows.