Word-of-mouth can be a powerful marketing tool for the pool and spa industry.

And in today’s world of high-speed everything, consumers can — and often do — share their experiences through a litany of Internet channels, including online forums, blogs, social media and user-review Websites such as Yelp.

Launched in 2004, Yelp allows visitors to search nearly every category of business or service — from dentists to restaurants to pool and spa retailers — and read ratings and reviews from other users. It has exploded in popularity of late, boasting an impressive 38 million unique visitors in August alone, according to the company.

But controversy has begun to swirl around Yelp. A number of small businesses earlier this year filed a class action lawsuit in federal court alleging that the site has repeatedly tried to sell advertising to businesses in exchange for altering, or even removing, their negative reviews.

The big question at hand is whether such actions can be considered extortion.

In the pool and spa industry, a number of retailers have been frustrated by Yelp’s policies governing reviews.

When one well-regarded company owner sought to correct a negative review, she said she was met with resistance, followed by solicitations to become a sponsored advertiser, not unlike the experiences of those businesses represented in the class action suit.

Another pool industry retailer with a number of positive ratings recalled contacting Yelp and asking to connect with a user who had posted an unfavorable, and questionable, review.

“When we see negative statements, we respond to them,” said Andy Hines, president/owner of Hines Pool & Spa in Austin, Texas.

But Hines said he was given the runaround by Yelp representatives, and it took nearly a month for the site to finally remove the review.

“I just don’t like how these reviews can proliferate,” Hines said. “I worry about the ones that are unfairly negative. But social media is here to stay, and all you can do is be proactive about it and address the issue.”

Indeed, Yelp does allow business owners to respond to positive or negative reviewers, publicly and in private. Some have chosen to do so, similar to the way the Better Business Bureau allows companies to explain how they’ve remedied a complaint.

But according to another pool and spa retailer whose business currently features two reviews on Yelp, policing one’s business and reputation can be a tricky proposition. He recalls one occasion in which he tried, without success, to connect with a negative reviewer on Yelp.

“It isn’t the 10 satisfied customers you usually hear from; it’s the one who had a bad experience,” said Brian Dresser, owner of Discount Pool Supply in San Diego. “That’s the one you have to worry about. But oftentimes it’s the anonymity of the poster that’s the real problem.”