CriticMarkup is a useful downloadable toolkit for authors and editors to track changes in documents. It is similar to how you track changes in Microsoft Word but is much simpler in use, less messy and has minimal interface. Instead of having a separate document view for a version with edits and a version without edits, you have a single document view with inline editing marks. There are different syntax marks for different uses.

So for instance {–text–} is for deleting text.
Example: “Don’t go around saying {–to people that–} the world owes you a living. The world owes you nothing.”

 {++text++} is for adding text.
Example: “To find sense in {++any++} copyright law on the planet” and so on.

The full syntax includes 5 marks:

• Addition {++ ++}
• Deletion {-- --}
• Substitution {~~ ~> ~~}
• Comment {>> <<}
• Highlight {{ }}{>> <<}

Demo video

Features:

• Track editorial changes in documents in plain text.
• Aimed at authors and editors.
• Dead-simple syntax marks.
• Easy to write, easy to read.
• Integrates with other tools including Sublime Text, Keyboard Maestro, BBEdit, Command Line and others.
• Syntax compatible with Markdown, MultiMarkdown and HTML.

Check out CriticMarkup @ www.criticmarkup.com