A March day got off to a bad start for Scott Willis and his mother with a minor car accident, but got worse when he went to a local care clinic called First Choice Emergency Room for treatment of his bruises.
"It was just a really bad experience for us," Willis recalled.
Especially, after he received a postcard a week later, telling him if he gave the clinic a rating of three stars or better on Yelp, Facebook or Google, they would give him a Starbucks gift card in return.
"I was really disgusted at that point," Willis said. "Those are people that should be caring for your well-being and your needs, not worried about what type of reviews they're going to get."
It's the kind of thing companies like Yelp, that rely on having authentic reviews, are worried about. A 2015 study by marketing research company Mintel found nearly 70 percent of Americans seek out others' opinions online before making a purchase, but only 59 percent trust the recommendations.
"If you are unfairly manipulating your reputation to appear a better business than you are, we think that's unfair and that disadvantages consumers," Yelp's Ian MacBean said.
In 2012, Yelp began flagging businesses with suspicious activity by posting its own Consumer Alerts. For example, a home renovation company offering a $50 gift card for negative review removal, a moving company offering $20 for positive reviews and a weight loss clinic offering discounts in exchange for five-star reviews.
Sometimes reviews are out-and-out false, planted by companies like the one MacBean showed CBS News, promising businesses two positive reviews for $5 on a website called Fiver.
"I've seen businesses generate hundreds of fake reviews," MacBean said.
He said they can span multiple listings and entire industries. His team even creates "decoy" businesses to catch fraudsters in the act.
"We might see something on Craiglist saying, 'Hey, I'm offering $20 for positive reviews on Yelp.' ... Odds are we're going to be among the first people to respond to that offer on Craigslist or Fiver or wherever else it may be," MacBean said.
Other companies are taking action as well. Amazon has sued more than 1,000 people in the past year for allegedly selling fake reviews.
"The worst problem is the purely fake reviews. They are just made up," said Mary Engle with the Federal Trade Commission, which tracks deceptive practices.
"Consumers need to know whether these reviews are independent, truly independent, or not ... Over 70 percent of consumers look at online reviews before they make purchases, so it is very important," Engle said.
In the first two days of this month, Yelp flagged 59 businesses including the clinic Willis said offered him the Starbucks gift card. CBS News stopped in to ask First Choice Emergency Room about their Yelp offer but were told to contact their corporate headquarters. We reached out to that clinic's corporate headquarters as directed but got no response.
"You're really hoping, whether it's positive or negative, to really get the factual information so you can make the best decision on where you choose to go get treated at or use your services at," Willis said.
There are a couple things you can do to try to determine if a review is real: check to see how many reviews the person has written -- Yelp says if they only write one positive review of a single business, that may not be as reliable -- and read reviews that offer more detail to get more specifics on positives and negatives of a particular business.