Even the least punctuation-aware consumer of the news must have heard in the last several days of the serial or Oxford comma.
It turns out that the serial comma is having its moment.
And none too soon, I say.
I'm a big advocate of the serial comma. It's the comma that comes before the penultimate item in a series of three or more items. I will not eat eggs, bacon, or toast contains a serial comma after bacon. In contrast, I will not eat eggs, bacon or toast does not.
Omit the serial comma, and a writer takes an unnecessary chance--much like a home cook who makes a tomato sauce without wearing an apron.
The chance is a misunderstanding. Consider the following sentence, which does not have a serial comma: I sat with my parents, Bob and Edna. Did you sit with your parents and two other people, whose names were Bob and Edna? Or did you sit with only your parents, whose names were Bob and Edna? The absence of the serial comma makes it unclear.
Actually, in the case just mentioned, the only way to make it clear with whom you sat would be to use a colon, if you sat with only your parents, or to use a serial comma, if you sat with your parents and two other people (Bob and Edna). I sat with my parents: Bob and Edna can only mean you sat with only your parents (and their names were Bob and Edna). I sat with my parents, Bob, and Edna can only mean that you sat with four people: your parents and two other people (Bob and Edna).