MediaSizer is a plug-in for use with Adobe Acrobat. It allows you to change the media size of pages in PDF document. For example you might want to change a Letter size document to A4 for distribution in the European market or A4 sized document to letter size for the North American market.
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.