A serial comma is the comma you use before the last item in a series of three or more things.
With the serial comma:
I went to the store to buy oatmeal, milk, and cookies.
Without the serial comma:
I went to the store to buy oatmeal, milk and cookies.
There are arguments to be made for and against it.
Why do I bring this up?
There’s an article by Jay Lindsay of the Associated Press called “Evangelists target spiritually cold New England” making the rounds. There’s nothing overly special about the piece — the headline summarizes it well enough.
But reader Jon brings it to my attention because of the comma issue.
Here’s a direct quotation from the piece. The lack of a serial comma gives it an entirely different (and very entertaining) meaning:
They say a reason for the region’s hollowed-out faith is a pervasive theology that departs from traditional Biblical interpretation on issues such as the divinity of Jesus, the exclusivity of Christianity as a path to salvation and homosexuality.
I’m pretty sure there are other paths to homosexuality besides Christianity.