PDF is now a very mature technology. After having been around for over a decade, one issue comes up repeatedly: backwards compatibility. If you have taken the plunge and upgraded to Acrobat 7, great! You have access to the latest and greatest in functionality; unfortunately, it doesn't necessarily follow that everyone in your audience is so lucky. What if they are running Reader 6, 5 or even 4?
Since version 6, Acrobat has offered a simple way to ensure backward-compatibility via the Reduce File Size menu item. Here's how to use it:
In Acrobat 6 or 7, select File > Reduce File Size.
Select the lowest version of Acrobat (and hence, Reader) that you would like to support, remembering that more features will be disabled in older versions.
OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.