If you work in PR, you might wake up in a cold sweat if you hear about a famous author writing a negative book about the company you represent. I've never worked in the profession, but I can imagine what it would be like. You get a call, then another. The firestorm erupts, mostly on social media and in your own inbox.

That's exactly what happened with Inc. Founders 40 member HubSpot this month after a book by Dan Lyons hit the shelves. It's an unabashed takedown and highly personal, a wild ride in startup land. Lyons worked there in 2013-2014 and went on to become a writer for the show Silicon Valley. My review covered all of the gory details, but the part I left out is perhaps the most perplexing of all: It might not matter.

HubSpot customers are rising to defend the firm. Oh, if only every PR professional had such a legion of loyalists who take over LinkedIn comments and fight with so much resolve to restore a company back to its former glories. In this case, the "glory" is the stock price, which dipped a few weeks ago by only a few points and has since rebounded. Customers are making a collective shrug over the book.

Dharmesh Shah, the Founder and CTO at HubSpot, posted a rebuttal of sorts on LinkedIn and admitted to some mistakes while defending a few of the most heinous claims in the book. If you read the comments and you work in marketing, you might wish you had so many staunch defenders.

One didn't mince words: "It is a pity that he didn't seem to learn much at Hubspot, because even at the most terrific job-place there is always something to learn, even from the boss who made Hannibal Lecter look like Gandhi."

Another praised Shah and basically took up the reins of defense: "What a wonderful zen counter to a pointed attack. Well-written, well-balanced and well-said."

What's really going on here? As you can guess, I have several theories.

First, there's nothing quite like a major company that does something that actually improves your bottom line. HubSpot makes inbound marketing software. Their app guides you through the process of creating and tracking content like blogs and social media, then linking that content to help you convert leads into customers. To be honest, if the software didn't work, the customers posting defensive comments on LinkedIn would not be so forgiving. When something works--that is, it helps you sell your product, attract new customers, and increase revenue--you defend it.

Lyons spent quite a few pages explaining that he didn't think the HubSpot software was that unique or powerful, but I doubt so many people would use it and keep paying the monthly fees if it was so terrible. (The Enterprise edition costs $2,400 per month, for example.) There's also a possibility these customers who pay so much feel they have to defend it--sort of like the person who spends too much on a Mercedes learning to accept that he will be driving it until the lease ends.

My other theory is that HubSpot is just really good at customer service. Maybe the software isn't having a dramatic impact or maybe it is, who knows? But at least these customers feel they are not being pushed off of a cliff. They are incredibly loyal for a reason. They view HubSpot as part of their "family" and have stayed loyal.

Apple has the same undeterrablefanbase. You can try and explain the benefits of using Android--the ability to load more cutting edge apps, the wider variety of phones available, the lower costs--but it won't matter. The typical iPhone user is a happy user. Things just work. They like being in the middle of a reality distortion field. It feels familiar and comfortable. Maybe the iPhone cracks too easily when you drop it, maybe app innovation has slowed. Doesn't matter. It worked at one time, and once you derive value from something, you stick close to the well.

I'm interested in your theory. What is HubSpot doing right to create such a wellspring of support? How is it even remotely possible to weather a storm like this? In some ways it seems as though the company is going to come out of this unscathed.

That's downright miraculous.