Content blockers block content. As @danprimack notes, that means that they block content.

It sounded like a really great idea at the time - whether the time was now, when iOS 9 now supports ad blockers, or perhaps when the time was before, when you added that ad blocker to your Internet Explorer web browser back in the day.

Ads and other unwanted content pop up on your phone, or your laptop, or your desktop, causing you irritation. So you decide to install an ad blocker or content blocker to free yourself from the anguish.

But guess what? I hope you're sitting down for this.

Content blockers block content.

Now perhaps I sound like Captain Obvious - and if you're actively using a content blocker, I need to explain to you that I'm referring to a hotels.com ad campaign - but any action that you take can have unintended consequences.

Dan Primack of Fortune has noted that someone with an active content blocker could be on a mobile phone, intending to buy something, and then be unable to buy it, or even see it.

After hearing initial reports from Chris Mason of Branding Brand, Fortune went and replicated the issues. First, it used an iPhone to go go the Bass Pro Shops mobile website, and looked at a picture of a boot, with the accompanying price.

Then Fortune visited the same mobile site, but this time did so with the Crystal content blocker enabled. Guess what? No boot, and no price, was visible.

You can see this example and other ones here. Fortune described a number of cases in which the content blocker blocked content. Maybe individual pictures won't load. Maybe the entire web page won't load. Or maybe the web page will load, but you can't load anything into the shopping cart.

However, there are "benefits" to the technology. Many websites, including the one that you are reading now, incorporate Google Analytics or similar analytic code to measure what you, the reader, are looking at. Content blockers can helpfully block this code from executing. Yes, you preserve your privacy...

...but at the same time, because the website doesn't know about your preferences, 60 year old men are unable to figure out why the websites that they visit serve up an endless array of Justin Bieber and Tampax news. Contextual ads are imprecise enough when they do know about you; what happens when they don't?

Fortune notes that Crystal is working on the specific issues that it reported, but also notes something else:

The trouble for retailers, of course, is that Crystal is just one ad-blocker. Another, Purify Blocker, currently sits at #5 in the App Store, and all of this is just one week after Apple unveiled its new operating system. Even if retailers reach out directly to one, they may be playing whack-a-mole.

It won't happen, but the advertising world is imagining a worst case scenario in which people try to use their phones to shop at mobile websites, give up in frustration because the mobile websites "don't work" (when in reality it's the content blocker that is causing the problem), and then eventually decide that the smartphone is pretty much worthless and that there's no need to buy that latest insanely great smartphone after all.

The more likely scenario is that people will buy the content blockers, hear about the problems they cause, turn them off, and then forget to turn them back on again.

Or maybe this is just this weekend's tempest in a teapot, and a blip - or a Blippy - on the landscape.