Commonly Forgotten Commas

Unrelated numbers are separated by a comma.

• In Florida in 1958, 875 acres of zucchini were mysteriously flattened in what historians now call The Great Zucchini Squash.

A comma comes between every third digit, counting from the right, in numbers of one thousand or over.

• 345, 770, 000 kilos 

Words identifying a person's title or position are set off from the person's name by commas.

• Old Aunt Lizzy, our town's resident crone, counted among her hobbies chewing tobacco and long-distance spitting. 

Commas are used to separate parts of addresses and names of geographical places or political divisions.

• Winnie T. Pugh, Ph.D., Treasurer, #5 Christopher Drive, Robin, South Dakota, is the person you need to contact.
• She dribbled her basketball from Baton Rouge, Louisiana to Biloxi, Mississippi, in record-breaking time. 

In dates, the comma between month and year is optional, but commas must set off the year whenever it immediately follows the day.

• The Beatles' first U.S. visit began on February 7, 1964, in New York City.
• On 15 March 1972 I ate my first in a long and distinguished line of Caesar salads.

A comma follows the complimentary close of letters.

• With lots and lots of sugary kisses,
  Old Aunt Lizzy 

Commas separate inverted names, phrases, etc., as in a bibliography, index, or catalogue.

• Harrison, George
• Hard Day's Night, A 

A comma comes after the salutation of a personal letter.

• Dear Younguns,
  Good news! Old Aunt Lizzy's Magical Mystery Winnebago will be rolling into your driveway next week. 

Use commas to set off interjections and other expressions that cause a break in the flow of thought.

• Well, here we go again.
• Why, I didn't know you cared! 

Use a comma to prevent confusion.

• First, the sentence without a comma:
  I saw Billy Bo Bob and Bubba at the ballet recital. 
• The meaning changes when commas are added:
  I saw Billy, Bo Bob, and Bubba at the ballet recital.

Two identical words should be separated by a comma for easier reading.

• They came in, in chiffon dresses and rhinestone tiaras.
  Whatever you do, do it with funk.