PDF Briefing: Commenting tools in Adobe Acrobat. By Simon Hurst

Introduction
Paper might be pretty useless as a method of storing data, but it does have the great benefit that you can scribble notes all over it, and distribute it around an organisation for others to add their comments. As we move away from using paper, it's important that the tools are available to allow users to work on electronic documents in the same way that they used to work on paper ones.

Adobe Acrobat includes a full set of review and commenting tools that far exceed the capabilities of a biro, post-it notes and a highlighter pen.