Better expressed "what is a primary source?" based upon the long-running discussion. From the comments of others, there are three basic ideas of primary sources: compilations of pure facts, historical documents and sources that are close to the subject. As one is not inclusive of the others, and people generally agree these are primary sources, the opening was revised accordingly.
Shortened the overly broad list of examples and moved it to a footnote, with specific examples of each of the three main "types" of primary sources.
Included the oft-noted idea that source typing can vary with application.
Revised the "use with care" statement to better frame it in context.
