A PDF file created from a Microsoft Word document contains less metadata than the original Word document. There is less potentially embarassing metadata, like deleted comments. For a lawyer, perhaps the scariest type of metadata would be a comment made by a client on a document that was then deleted, but might be somehow viewed by a third party using a metadata viewer tool.
But the conversion to PDF does not cleanse a document of metadata– by design. That is an important point. Lawyers are busy people and they move quickly through many tasks. So some subtle distinctions may slip by like while a deleted comment may not transfer via a PDF conversion, a comment in the document can still be transferred to the PDF even if is not visible while normally viewing the PDF file.
So lawyers do need to be concerned about metadata scrubbing in PDF documents. And I direct your attention to two recent blog posts that amount to a conversation between Dave Stromfeld, Acrobat's Senior Product Manager, and blogger Sharon Nelson on the various tools included within Adobe Acrobat to view and remove metadata.
The posts are Adobe's Advice on Purging PDF Documents of Metadata and Adobe Offers More Helpful Metadata Scrubbing Tips. There are so useful ideas here for both lawyers and law firm IT departments.