In response to my advice on the correct use of semicolons and colons, John writes, "That was a superb semicolonoscopy; I thank you for it."

And I thank you, John, for the laugh.

My advice consisted of three principal points:

1. Think of the semicolon as a closed door, and the colon as an open door. The semicolon separates; the colon introduces.

2. Even as it separates, the semicolon suggests a connection, as in "Javon was two hours late; Gabrielle was worried" and "Ask not what your country can do for you; ask what you can do for your country."

3. To be grammatically correct, you need a complete sentence on either side of a semicolon, as in "It finally snowed; I'm going for a ski" rather than "Although it finally snowed; I'm not going for a ski."

Suzanne's confidence was shaken by a missing apostrophe in a misspelled word: "I have been considering buying a new car … I was seriously thinking a new Mini Cooper would be a fun small car to own until I got a glossy promotional postcard for an event … that said, 'We are going to sell 20 Mini's in 20 hours! and your the one that wins!'

"I hope the lack of attention to detail in the Mini Cooper marketing department does not extend to the manufacturing of the cars."

Jim writes, "A few weeks ago, a [newspaper] headline writer fell into a trap with the headline, 'Yes, Virginia, Minnesota really is nice.'

"Did he mean the city of Virginia in Minnesota is nice, or was he paraphrasing 'Yes, Virginia, there is a Santa Claus'? — affirming that Minnesotans are nice?"

Those headline writers are clever people, so my guess is that the comma was omitted intentionally as a play on words. Jim's query, however, underscores the importance of correct comma placement.

Be careful not to omit the second comma when commas are used to enclose. Use paired commas (as you would parentheses) before and after:

1. A title when the title follows a name, as in "Alan Page, associate justice of the Minnesota Supreme Court, wrote a stinging dissent."

2. The parts of an address, as in "Minneapolis, Minnesota, is where many nice Minnesotans live."

3. The year when the day's date is given, as in "February 22, 2013, is a special date for me" (but omit commas when only the month and year appear, as in "February 2013 was a gloriously snowy month").

4. A name or a form of direct address, as in "Thank you, friends, for congratulating me on becoming a grandfather."

As Barb points out, comma placement can determine meaning in sometimes dramatic — and potentially unfortunate — ways: "I've seen a T-shirt that says: 'Let's eat Grandma. Let's eat, Grandma. Commas save lives.' "

In "Eats, Shoots & Leaves," Lynne Truss illustrates the power of punctuation with this offensive sentence, "Woman without her man is nothing," coupled with its equally offensive counterpart, "Woman: without her, man is nothing."

Stephen Wilbers offers training seminars in effective business writing. E-mail him at wilbe004@umn.edu. His website is www.wilbers.com.