Commentary: Accounts of the affair say that the two exchanged something like 20,000 to 30,000 emails, certainly enough to cover James Joyce’s “Ulysses,” the “Odyssey” on which it was based and Leo Tolstoy’s “War and Peace.”

Agood sex scandal always has something to teach us. Usually, what we learn in kindergarten: “Keep your hands to yourself.” And the one affecting our top military leaders is no exception. Will we learn that there is no such thing as privacy on the Internet? Apparently not.

But the relationship between Jill Kelley, 37, a Tampa, Fla., socialite who seems to have socialized largely on borrowed money that the lenders now want back, Marine Gen. John Allen, 58, the U.S. commander in Afghanistan, has an especially instructive lesson: time management.

Quoting supporters of Allen, The Washington Post said, “The problem is, his allies said, is that Kelley was a prolific emailer. And so is Allen.”

Prolific doesn’t even begin to describe it.

Accounts of the affair say that the two exchanged something like 20,000 to 30,000 emails, certainly enough to cover James Joyce’s “Ulysses,” the “Odyssey” on which it was based and Leo Tolstoy’s “War and Peace.”

In short, the two generated a lot of reading material. If they emailed each other for two years, according to some accounts, that’s 5,000 to 7,500 emails each per year per correspondent, about 14 emails a day at the low end, 20 at the upper end. If the correspondence lasted four years, according to other accounts, that’s still a production rate of seven to 10 emails a day.

And these are people who had their hands full with paperwork. The military generates tons of forms that have to be filled out and socialites are constantly drafting bread-and-butter notes.

The Wall Street Journal speculates that that large volume could be due to the email system generating multiple copies — “As replies piled up on replies in various email chains.” — a development that’s hardly good news to people hoping to conduct a surreptitious online romance.

So far, the most salacious thing said about the emails was that they were sometimes “flirtatious” or — and here’s a whole new literary category — ”potentially inappropriate,” whatever that means. (“Hey, you guys! What’s say we go out and spray paint some potentially inappropriate graffiti on abandoned warehouses?”)

Bringing this idyll of the inbox to an end was an email to Allen from “Kelleypatrol” warning that she was a “seductress.” The language must have alerted Allen that Charles Dickens or the Bronte sisters were hot on his trail.

He forwarded the tipster email to Jill Kelley who sent it to an FBI friend and from there the investigation spread to engulf CIA Director David Petraeus and his muscular girlfriend, Paula Broadwell.

To close the circle on our lesson of why you should never trust the Internet, it turned out that the FBI agent had earlier emailed photos of himself bare-chested to Kelley. Soon we’re likely to be treated to those sordid little vignettes — where else but on the Internet.

Dale McFeatters can be reached at McFeattersD@SHNS.com.