If Amazon has its way, you might be seeing fewer five-star reviews of your favorite products on its site. 

Last week, the e-commerce giant filed a lawsuit against more than 1,000 people who offered to write up fake online product reviews for money from websites like Fiverr. While lots of positive reviews may provide a short-term boost for businesses, Amazon alleges that, if customers discover that these reviews are actually fake, they can "significantly undermine the trust that consumers and the vast majority of sellers and manufacturers place in Amazon, which in turn tarnishes Amazon's brand."

Matt Moog, CEO of Power Reviews, a company that works with 1,000 different retailers and brands to collect and verify customer reviews, says that the number of fake reviews is actually a very small percentage of all reviews online; they are more likely to be submitted for small, local businesses than larger brands. 

"If you're selling a product nationally, in major retail stores, there is much more for you to lose by committing any kind of fraud," says Moog. "It's usually a single rogue employee who has a bad idea, is discovered, and never does it again." 

Want to vet the credibility of a product's reviews? Here are five ways to spot a fake online review:

1. Reviews are submitted in "rapid-fire" fashion.

Moog says that one of the first things Power Reviews does is look for signs that reviews are actually spam--for example, if several were posted within a few minutes of each other. Or, even if postings were spread out over the course of a few days, if they all contain similar language or phrases to one another, they're most likely fake.

2. Glowing language.

While you might dream of getting only five-star reviews, seeing all positive reviews isn't likely to convince a customer to buy a product or eat at your restaurant. A joint study between Power Reviews and Northwestern University's Spiegel Digital and Database Research Center found that shoppers are more likely to purchase a product with an average star rating between 4.2 and 4.5 than one with a 5 star rating, because they review mixed ratings as more credible than those that are overwhelmingly positive.

3. An abundance of personal pronouns. 

Reviewers often try to establish themselves as genuine by using lots of personal pronouns--I, we, my. But people usually don't start every sentence in a two-paragraph long review with "I." Use too many personal pronouns and the review sounds too stiff, and not like something a real person would write, Moog says. 

4. Focusing on personal details more than the place of business.

Any review that talks too much about details that aren't related to the business is most likely written by someone who is faking their experience. For examples, reviewers who mention "my vacation" over and over again, or how much "my husband" enjoyed the bicycle. Deceptive reviewers do this to "emphasize their own presence," to use these seemingly personal details as evidence that they were there, according to a 2013 study on deceptive online reviews by researchers at Cornell University.

5. No knowledge of the layout of a physical storefront.

The Cornell researchers found that fake reviews are less likely to contain language about spatial configuration (i.e. small, bathroom, location). Most of the time, these reviewers have never been to the hotel or store they are raving about, so they can't talk about any specifics in regards to layout or furnishings.