Jeff Weintraub cites an example illustrating the importance of the Oxford comma:
The documentary was filmed over three years. Among those interviewed were his two ex-wives, Kris Kristofferson and Robert Duvall.If only for the manly reputations of Kris Kristofferson and Robert Duvall, who would love to finish out their careers without the sexually-charged hectoring of paparazzi, make sure to use Oxford commas regularly.
And yet ... and yet. The Wikipedia article on the topic demonstrates that the Oxford comma can, at times, increase rather than decrease ambiguity:
An example would be a list reading:What to do? Are we to slavishly deploy the Oxford comma and commit ourselves to the view that Ayn Rand and god are the same moral monster?
My mother, Ayn Rand, and GodThe serial comma after Ayn Rand creates ambiguity about the writer's mother, leaving it unclear whether this is a list of three people – (1) mother, (2) Ayn Rand, (3) God – or two – (1) mother, who is Ayn Rand, (2) God.
Without a serial comma this would read:
My mother, Ayn Rand and God– which is ambiguous only if the reader is prepared to accept the unlikely interpretation "My mother, who is both Ayn Rand and God".
The careful reader of these examples will notice that the true impediment to clear writing is not the misplacement of commas but the creation of ambiguity. If our commas foster clarity, then Ayn Rand and god can keep their distinct seats in the pantheon of history's most deservedly despised misanthropes, Kris Kristofferson can resume his respectably non-wife role in the history of country music, and Robert Duvall can resume stealing movies with cameo roles.