Ruth E. Thaler-Carter: Dots between units are too hard to see in many typefaces and sizes, although raised dots work well. Parentheses and slashes make the area code look optional. Since most major metropolitan areas have moved to 10-digit local phone numbers, making the area code a mandatory element of dialing any number, I use dashes.

Alicia Rosov: I assume those are en dashes. :)

Rob Ault: I also like the "dot" option. It looks very European and dot-com.

Jennifer German: C. would be correct if I were European!

G. Miki Hayden: That's the least use, but I do use that form because I think the style is cool.

L. L. Thrasher: We just went to ten-digit local numbers where I live, and the style is to use the hyphens so we might as well make it consistent. Besides, we already use the hyphen in long distance numbers: 1-800-555-1212.

Yocheved Golani: The immediacy and fewer keystrokes have been my impetus to record phone/fax numbers this way for years. At first I was derided for preferring this European format, but I am noticing its increased usage everywhere.

Bob Allen: Other choices look a phony attempt to be hip. C looks like an Internet address for a server.

Lisa Karam Middleton: Although it has always been our style to use example 4, we recently changed to example 3, feeling it was looked more sophisticated.

Jacqueline S. Garnier: This is just personal preference (although I try to press it on my people to do it this way). I find the others harder to read, especially the first with a "/". We use a lot of san serif font and I find that the slash very difficult to discern from some numerals in san serif. The hyphen just seems to provide more space without cluttering the number as the slashes seem to do. (I also live in an area that requires all 10 numbers, and I find that to put the first 3 numbers in parens as if they are optional is confusing to people new to our region.)

Charlotte Fox Luttrell: B is easiest on the reader's eye. A -- slashes and hypens -- ugh! C. periods -- interupts the reader. D. parens and hypens -- ugh?

Lori Seng: This one is all a matter of style and is dependant upon the image that the company wants to present. I'm in a technology-based field, and using the dots instead of the dashes presents a "techie" feel.

Mark H. Bloom: I also like the third choice, but I struggle to remember to use it. All are correct, so it is merely a stylistic preference.

Amy Goldyn: This is a personal preference because it translates via e-mail and on Internet forms.

Carrie Garbas: I also use (c) informally, however.