The point is that the article's title is another "unexploded pun", the principle of which is a central theme to the article; it is referring to Booth's analysis

The point is that the article's title is another "unexploded pun", the principle of which is a central theme to the article; it is referring to Booth's analysis of one of the sources of the Bard's greatness: Shakespeare achieves this by weaving incredibly rich networks from the same kinds of “substantive nonsense and nonimporting patterns” that pop up in slang, jokes, songs, and nursery rhymes. Those dense networks of patterns, Booth posits, are “the principal source of the greatness we find in Shakespeare’s work.” edit: formatting