"So what happened to the comma in this process? Well, between the 16th century and the present day, it became a kind of scary grammatical sheepdog. As we shall shortly see, the comma has so many jobs as a "separator" (punctuation marks are traditionally either "separators" or "terminators") that it tears about on the hillside of language, endlessly organising words into sensible groups and making them stay put: sorting and dividing; circling and herding; and of course darting off with a peremptory "woof" to round up any wayward subordinate clause that makes a futile bolt for semantic freedom. Commas, if you don’t whistle at them to calm down, are unstoppably enthusiastic at this job."
~ Eats, Shoots & Leaves ~ Lynne Truss
x-posted to barlow_girl, literaryquotes, and grammarpeeve