This particular punctuation mark might seem a little pretentious sporting such an academic name. But using it correctly can eliminate confusion. Here is a great example of the reason you should use the Oxford comma, sometimes known as the serial comma. It appeared in the Sunday, January 11, 2009, edition of the Pittsburgh Post-Gazette on the editorial page. We’ll get to it in a minute.
In a series of three or more items separated by commas, the Oxford comma is the comma that separates the final two items and comes just before the conjunction. “Go to the store and get eggs, bread, milk, and celery.” Some style manuals advocate omitting this comma. That would not be a problem in the previous sentence, but it some cases, the omission creates ambiguity or momentary confusion. “My favorite foods are steak, pizza, macaroni and cheese and crackers.”
See if you can spot the problem in the following sentence: “A recent Post-Gazette review of Allegheny County restaurant inspections turned up some pretty disgusting conditions — dead roaches on the floor, live ones scurrying across steam tables, rodent droppings and foods of all sorts being kept at unsafe temperatures.” (italics mine)
The end of that sentence had me wondering just what the safe temperature for rodent droppings might be.