Amazon

True story: Recently some friends purchased a GPS locator for their daughter and were having trouble getting it to work. They brought it to me for help -- I'm the Geek Squad for my friends and family -- but I couldn't solve the problem either.

My friends were puzzled: "It had a five-star rating on Amazon!"

I pulled out my laptop and checked the product page. Sure enough: 37 five-star reviews. But this thing was undeniably a lemon. What the heck?

Mystery solved: Every single review was a fake.

Fake news, meet fake reviews

What's a fake review? Exactly what it sounds like: a review posted by a company employee, paid individual or anyone else with a vested interest in selling more product. Last year, for example, skin-care brand Sunday Riley was caught encouraging employees to post fake reviews on Sephora.

This is a serious issue, and in my capacity as The Cheapskate, I see it all the time -- mostly with products sold by small or foreign companies.

Fakespot/Screenshot by Rick Broida/CNET

One or two fakes: no big deal. Lots of them: now you've got an artificially inflated product rating. It's way too easy to glance at a four- or five-star average and think, "OK, this must be good!" Few folks are going to take the time to dig into each and every review -- or every reviewer -- to look for red flags.

Here's a great example: You're in the market for a GoPro-style action camera. A real GoPro will run you hundreds of dollars, but there are countless knock-offs priced as low as $40 to $50. But they can't possibly be as good, right? Well, they look like GoPros. They come with lots of accessories. And here's the kicker: high marks from dozens or even hundreds of reviewers. Sold!

The problem is, dozens or even hundreds of those reviews might be fake -- or at least questionable. It's hard to know for certain, but there are telltale signs. More on that below.

But shouldn't Amazon be doing something about this? A few years ago, the company promised to start cracking down on incentivized reviews, meaning those posted in exchange for free or discounted products. Sure enough, I no longer see reviews with that disclaimer embedded -- but that doesn't mean there's been a decrease in illegitimate reviews.

Read more: FTC settles Amazon case over fake reviews

Indeed, in my world, where I frequently write about lesser-known tech brands and products, not much has changed. So let's talk about the tools you can use to spot fake reviews and -- just as important -- how to interpret the results.

X marks the Fakespot

First up is Fakespot, a free site that analyzes product reviews to help you separate the wheat from the, well, fake. All you do is copy and paste the link to the product page, then click Analyze.

You can also use a browser extension for Chrome, Firefox and Safari, which makes it even simpler: Just click the Fakespot icon in your toolbar for instant analysis. It's also available for Android and iOS so you can use use Fakespot on the go.

Fakespot originally focused its algorithms on Amazon alone, but later added TripAdvisor and Yelp support. Last week, the company introduced search engines for Best Buy, Sephora, Steam and Walmart. (Incidentally, of those new additions, Fakespot found that just over 50 percent of Walmart reviews were "unauthentic and unreliable," while fewer than 5 percent of Best Buy reviews were the same.)

The system analyzes both reviews and reviewers, looking for questionable spelling and grammar, the number of reviews, purchasing patterns, mismatched dates and other telltale signs of suspicious review activity. For example, a reviewer who's new to Amazon, has posted only one review and uses lots of words like "great" and "amazing"? That review is almost certainly going to be marked "unreliable."

After the analysis is finished, Fakespot provides a letter grade based on the total number of reviews and how many were unreliable. And that's where things can get a little confusing: If you're looking at one of the aforementioned cameras and it gets an "F" because, say, 57 percent of the reviews were marked as unreliable, you might be a lot less inclined to purchase it.

Ah, but does that mean the product itself is bad? Not necessarily. More on that in the next section.

Next, there's ReviewMeta, an Amazon-only analyzer that takes a very different approach, according to developer Tommy Noonan. Although it's functionally similar -- paste in an Amazon link or use one of the browser extensions -- ReviewMeta merely strips out or reduces the weight of certain reviews, then leaves you with an adjusted rating.

Screenshot by Rick Broida/CNET

In other words, instead of the letter grade, which can be misleading, ReviewMeta shows you what the Amazon average rating would be if the questionable reviews didn't exist.

Here's where it gets interesting: Often, Fakespot and ReviewMeta reach very different conclusions about a product's reviews. I've seen it happen where one tool gave the reviews a pass and the other said they were mostly fake.

Grading the graders

What can we make of all this? If we can't always trust the reviews shared by Amazon customers, can we trust the reviews of those reviews?

It's a challenge, to be sure. As Noonan told me, "It's impossible for someone to definitively determine whether a review is 'fake' or 'real.' Not even a human can do it, so it's impossible to really determine how 'accurate' Fakespot or ReviewMeta is."

Noonan says he designed ReviewMeta with that in mind, and it's why he shares as much detail as possible on the reports. "The tool isn't really intended to just give you a black and white answer," he says, "but more to show you all the data that we possibly can and then let you make your own decision."

And I think that's the key takeaway here: Be aware that any product's rating might be artificially inflated, and use tools like Fakespot and ReviewMeta if you think you're not getting an accurate picture. At the same time, be aware that these analyses might have accuracy issues as well, and that they don't necessarily reflect the quality of the product itself.

The Atech earbuds shown throughout this story is a perfect example. They have a 4.3-star average rating from 16 Amazon customers, suggesting a solid product. According to Fakespot, however, only about 62 percent of those reviews are reliable. ReviewMeta puts the number at just 50 percent, and leaves the earbuds with a lower rating as a result: 3.9 stars.

My advice: Take everything with a grain of salt. Don't believe everything you read. Do use common sense. That's good advice whether you're shopping on Amazon or, you know, looking at the internet.

Have you had a run-in with fake reviews? Ever purchased something knowing full well the reviews were questionable? What was the outcome?

Originally published on Feb. 20, 2017.

Update, March 4, 2019: Added new information.