FORT LAUDERDALE, Fla. - Everyone's a critic, as the saying goes. Nowhere is that more true than in cyberspace.

The number of user-generated ratings sites has exploded in recent years, with citizen reviewers posting millions of opinions about everything from their local dry cleaner to their latest hotel stay.

Some sites offer a place to rave or rant. But others have developed rankings and search functions, allowing users to zero in on top-rated services and products.

Cruisecritic.com can show you which ships cruisers think are best for fitness buffs. Amazon.com allows readers to rank the books and movies they buy. Epinions.com features top 10 lists, generated from user reviewers, for products as diverse as televisions and strollers.

Is it consumer empowerment or an imperfect source of information? It seems to be a little of both.

That's why consumer advocates, even some in the user-opinion industry, advise consumers to consider more than personal ratings when making big-ticket decisions.

"Balance those reviews with information from the outside world and never neglect your gut instinct," said Angie Hicks, co-founder and chief marketing officer of Angie's List. The site posts more than 40,000 new user reviews monthly of contractors, auto mechanics and doctors in 200 metropolitan areas, including South Florida.

Most opinion sites, including Angie's List, take advertising from business their users may review, and some sites give better Web page placement for a higher fee.

Even the conscientious sites can't completely control quality and screen bias, said John B. Horrigan, associate director for the Pew Internet and American Life Project.

Business owners can log on anonymously and praise themselves or bash competitors. Consumer reviews also are skewed by the tendency of posters to have had extremely positive or negative experiences rather than average ones, Horrigan said.

Despite imperfections, others think user review sites are part of a consumer revolution. Instead of gathering a few suggestions from friends and neighbors before hiring a plumber or buying a car, shoppers can get recommendations from thousands before making a choice.

Carol Higgins, a television producer for Miami-Dade County, turned to Angie's List about a year and a half ago when she was looking for a painter and handyman.  Although Higgins usually polls friends, "they don't know everyone out there, and I wanted to feel confident the person I used was good," she said. She found the perfect painter and since has hired a plumber, a locksmith and a cleaning service based on Angie reviews.

Some user-generated sites, including Angie's List, charge membership fees - something Higgins, who pays about $67 annually, thinks helps keep out self-promoting business owners and consumer vigilantes. Hicks said the company, with about 750,000 members nationwide, watches for posters filing under multiple names and allows businesses to respond.

Some free services like South Florida newcomer Yelp.com say they do the same thing through monitoring software and filters. Yelp.com is one of the fastest-growing opinion sites with 21 million visitors over the past 30 days and 6 million reviews worldwide.

Spokeswoman Stephanie Ichinose said the community's most active "Yelpers" help police postings, an observation echoed by other sites like TripAdvisor.com, where 25 million people monthly go to view rankings of attractions, restaurants and hotels.

Opinion site fans hope that spirit won't be dampened by a handful of libel lawsuits, filed against posters over the past few years, by business owners angry over bad reviews.

Bob Jarvis, a constitutional law professor at Nova Southeastern University, said the reviewers almost always should win as the First Amendment protects freedom of speech "and protects pure opinion."

"The problem is you could be ruined financially if you have to defend yourself against the business owner," Jarvis said. "But the business owner gets the negative publicity, plus brings attention back to the original post. It's a conundrum for both."

A CRITICAL EYE

1. Carefully evaluate any one review, especially if anonymous. They can be biased.

2. A large number of similar reviews and comments will be more reliable than a small number.

3. Note the qualities of a product or service that a reviewer uses to form his or her opinion.

4. Read a Web site's description of how it conducts reviews and the experience of its reviewers.

5. Some review services test products. Check the details of how they were tested."Balance those reviews with information from the outside world and never neglect your gut instinct."

- Angie Hicks, co-founder and chief marketing officer of Angie's List

(c) 2009, Sun Sentinel.

Distributed by McClatchy-Tribune Information Services.