SAN FRANCISCO – One of the great frustrations of someone who writes about the adult industry from within it comes in reading articles about the same subjects written by people on the outside looking in.

Among other things, I’m consistently mystified by the credulity of journalists when it comes to claims made about (and by) the porn business, many of which are quickly and easily debunked with even a cursory effort.

How many times have you seen written or heard said that the adult industry is “a $97-billion-a-year business,” for example? Now ask yourself an important follow-up question: Where did that figure come from?

If you research the answer, you’ll find it traces back to an old infographic first published about 10 years ago on the site Top Ten Reviews. Go further and research the sources cited by Top Ten Filter Reviews, and you’ll find they took a hodgepodge of estimates from magazines like AVN, combined them with pulled-from-the-ass guesses coughed up by sensationalizing anti-porn crusaders, tossed in a few random, entirely source-free claims from various other publications, added it all together and somehow came up with $97 billion.

If you don’t feel inclined to do such research, alternatively you can just ask yourself a simple question: How likely is it, really, the number of new adult sites launched, revenue earned, etc., is exactly the same now as when the infographic was first published? After all, if you visit the page linked to above right now, then again a year from now, it will give you the same information. And yet, the information there seems to be considered “current” by a lot of journalists and academics who look at it and really ought to know better.

So, is the $97 billion figure right? Wrong? Is it even close? Who knows?

Most likely, based on dozens of off-the-record conversations I’ve had with companies that process online transactions and the site owners whose income relies on those transactions (both in my current capacity as a writer and from my days as an advertising affiliate), the figure is way, way too high — but good luck definitively determining this to be the case, given how far-flung and generally unavailable is the real data one would need to have in hand to come up with a more sensible estimate. Even the likes of Forbes have had a hard time coming up with a solid estimate, stymied in their efforts by the inability to acquire reliable data.

Another indication people writing about the industry from the outside might not exactly have their finger on the industry’s pulse comes when they write about the financial health of the industry and act like a decline in the industry’s aggregate revenues is a new thing.

“It won’t go out of business anytime soon,” wrote Heather Hunter (no, not that Heather Hunter, this Heather Hunter) for Lifezette.com, “but for the first time in the digital era, the porn industry has begun to struggle.”

Give me a second to recover from laughing my way out of my chair.

As anybody who works within it already knows, the adult industry’s current “struggles” are not new. In fact, those troubles arguably began well before the dubious $97-billion revenue estimate first surfaced in 2007.

To be fair, Hunter does acknowledge Kink’s troubles started more recently than her opening paragraph suggests, noting Kink’s site membership has “decrease(d) by 50 percent in the last three years.” Three years is still significantly off when it comes to pegging the start of the general industry decline she’s addressing here.

Of course, if you’re already cherry-picking your facts to make a point, I suppose there’s no further harm in ignoring small items like the linear nature of time in order to buttress your argument.

“Porn exploded in the videotape age, then moved to DVDs, then to internet memberships,” Hunter wrote. “Now, it has moved to free websites, which means sharply lower revenues and cutbacks on models, directors, accountants, lawyers, and other staffers.”

As a guy who launched his first free porn site in 1997, I almost broke my nose with the severity of the involuntary facepalm I executed upon reading the above. Now porn has moved to free websites? Are we talking about internet porn in terms of a geologic time scale kind of “now,” or what?

Everything above could be written off as nitpicking, except for one thing: When Congress asks people to come talk to them about things like the “problem of internet porn,” they don’t invite people who have a clue. They invite people like Heather Hunter.

Actually, it’s worse than that: Congress invites people like noted porn “expert” and not-at-all-crazy person Judith Reisman.

As such, I’d better sign off on this piece with an apology to Hunter and others who write about the porn industry for non-porn publications. After all, people like Hunter may not have their facts entirely straight, but at least they don’t waltz around arguing the reason people occasionally shoot up college campuses is their minds have been warped by pornography-generated “erototoxins.”