Need to find a good plumber, hairdresser or auto mechanic? If you're like a lot of people, you're happy to turn to online ratings services.
But how trustworthy are the opinions?
Here's what you should know about the companies Consumer Reports Money Adviser examined, listed in alphabetical order.
Cost for consumers: Varies according to length of contract and special offers; regularly $39 a year in Pittsburgh.
How it works: Companies set up free online profiles or involuntarily get one when a member rates them. When they get two reviews and a B average or better, and there are no alerts about them, they can pay to advertise and must offer discount coupons that "position your business to rotate on page 1 of search results," Angie's List says.
Caveats: The ability of A- and B-rated companies to buy their way to the top of the default search results skews the results. Angie's List misleads consumers by prominently promising that "businesses don't pay" and that it's a consumer-driven service supported by membership fees. But almost 70 percent of the company's revenues come from advertising purchased by the service providers being rated.
Cost for consumers: Free
How it works: Anyone can search Google+ Local by city, state and business type to find reviews, which are simple one- to five-star ratings and commentary. Google is mum about how an overall rating is calculated beyond saying that it's based on user ratings -- no details on how users are verified -- "and a variety of other signals to ensure that the overall score best reflects the quality of the establishment," according to the Google+ Local website. To write a review, you must create your own personal Google+ profile, typically using your real name, which provides something of a reality check.
Caveats: Google encourages businesses to reward their fans with coupons and to try to resolve customer service problems. But this can skew the ratings positively, because assuaged customers can always delete their previously negative reviews.
Cost for consumers: Free
How it works: Anyone can look up a company on Yelp to see its overall rating and individual reviewers' ratings and comments. To write a review, you need only set up a username and provide your email address and ZIP code. That creates a profile where your reviews are gathered. The more prolific you are, the more trusted and "known" you become in Yelp circles.
Companies appear on Yelp involuntarily, but they can claim their page and gain access to tools that let them contact reviewers publicly or privately through the site to work out problems.
Caveats: A company's ability to make amends with a negative reviewer -- while good from a customer's perspective -- undercuts the integrity and accuracy of the ratings, because placated gripers can change their review at any time.
And rated service providers can buy sponsored search results and put them at the top of the list for someone searching for, say, a restaurant in Los Angeles.