CHICAGO, Feb. 6 (UPI) -- Last fall a controversy erupted when the details of the assassination of former Lebanese Prime Minister Rafik Hariri were revealed in a United Nations report -- after a cunning reader spotted a "track changes" mistake in the layout of the document. That political controversy is one of the latest tempests to emerge over "metadata," or data about data, contained in Microsoft Word and Adobe PDF documents, easily accessible by millions of readers over public networks like the Internet, experts tell United Press International's Networking.

By clicking on the "track changes" feature in Word, readers can see who wrote a particular document, when it was written, what edits were made and comments made by editors and redactors -- something government officials, working with official secrets, or confidential information, most definitely don't want released for review in the court of public opinion. By deleting text blocks -- used to blacken out information in PDF files -- readers can see what was originally written there. By Gene Koprowski