I attach PDFs to my projects to track changes on print items I manage. I recently discovered the mark-up tools available in the attached PDFs and am very excited about the possibilities.
However, what would greatly increase the usefulness is the ability to attach uploaded files to an email from Clarizen. Adding an attachment option to the email window would be great. Also adding an email button to the File Details screen would make it very easy to send project files to those who don't have Clarizen. When using an email button from an attachment, I would want to be able to link it to or reference specific tasks or Milestones within the project.