Google has made it easier to view and organize all comments made on user drawings, documents and presentations posted in Google Docs - by clicking on the "Comments" button at the upper right of the editor window, one can view a complete history of their discussions. There, one can post replies, resolve previous comments, add links to comments or change notification settings:
Also, using Google's Optical Character Recognition technology, users can now search through and copy highlighted text from a scanned PDF:
Also, text from PDFs and images uploaded into Google Docs is now searchable.
Hat tip to Ian Kilpatrick, Software Engineer.