Have you have ever looked at a PDF and wondered who created it, how you could contact the creator or what the font was you saw in the PDF?
The answers can be revealed at the push of a key. If you’re on a Mac press Cmd+D, or on a PC Ctrl+D and you will be presented with a Document Properties box. Provided the creator of the PDF has filled in some of the information, you should be able to find out who created the PDF, what software was used, and when it was created. You can also see all the fonts that have been used in the document - useful if you see a font you like, or want to request a font to use in another document. You can also see what, if any, security has been applied to the document.
All of the above information is available to users of Acrobat Reader 9. If you have a full version of Acrobat you have access to even more information - detailed description including keywords, camera data for photos, full contact details, address, website etc, (providing the creator filled these in) and DICOM (Digital Imaging and Communications in Medicine) information.
We always try to fill in document properties on all of our files because it helps when filing or adding to a content management system. If you use software like Adobe Bridge the document properties are displayed under the IPTC* Core tab.

*IPTC is the standard developed by the International Press Telecommunications Council. Some software enables users to insert and edit IPTC metadata in digital files.