The Mining of Metadata, Navigating the hidden ethical dangers of discovering hidden information in electronic documents, by James T. Yand (Sept. 2008). Excellent article reviewing the various state and ABA opinions regarding the mining of metadata in a lawyer's document (last visited Sept. 10, 2008).
The National Security Agency (NSA) released guidance to help other federal agencies avoid dangers of documents made available in Adobe PDF or Microsoft Word formats. The study, entitled, "Redacting with Confidence: How to Safely Publish Sanitized Reports Converted from Word to PDF," summarizes the actions to ensure that confidential information contained in Word or PDF files is not accidentally disclosed.