Just as roadway signs help drivers find their way, punctuation marks guide readers.
Both types of guideposts have specific functions, as well.
Tailgating the previous Brighter Writer column, which was brimming with bad-driving analogies, let’s consider how those little dots, curves and line segments on the page help your readers navigate their way to your message:
A period at the end of a sentence is a stop sign. Period.
Commas are like the ubiquitous yellow signs offering any of a number of advisories—such as a curve left or right, an intersection (and its configuration), two-way traffic, or a pedestrian crossing. Likewise, the comma has myriad uses: in series, nouns of direct address, appositives and so on. They are elaborated upon here.
A colon, like a “Speed Zone Ahead” sign, heralds something imminent that warrants the reader’s attention: a list or a lengthy quote or excerpt.