If you'd like to update your PDF documents for more streamlined online browsing, why not just convert them into digital Flash publications -- for free?
UK-based YUDU offers a free online service for accomplishing just this task via its YUDU Freedom service. The service converts PDF documents into Flash publications for upload or email distribution. Such publications may also be hosted for free.
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.