PowerPoint offers several powerful tools to help you build a presentation as a collaborative effort.
You can attach yellow sticky-note comments to slides in your presentation. These notes can be helpful when you're passing around a presentation file for comments. They don't appear during the presentation, and you can use View, Comments and Changes to either show them or hide them when you're working on the slide.
To create a comment, do the following:
Pick the slide you want to contain your comment.
Choose Insert, Comment. PowerPoint creates a sticky note, places your name on it (taken from the Tools, Options, General, User Information box), and the date, and displays the Reviewing toolbar. ...