About a third of American travelers who research trips via the Web read reviews written by fellow travelers, according to Forrester Research. Of those who book hotels online, a third have changed plans based on other travelers' comments. A new survey by online market researchers Compete, Inc., shows that 56% of respondents consider "consumer-generated content" to be credible, vs. 36% who trust descriptions created by a hotel or other travel supplier.

In response, a slew of travel sites are introducing or expanding consumer reviews and exchanges, from online agencies such as Priceline.com (which recently added Zagat hotel ratings to its own customer reviews) to the Florida tourism office's VisitFlorida.com, which plans to launch tourist-generated blogs and videos this fall. Even Andrew Harper, whose opinionated Hideaway Report newsletter caters to wealthy, discerning travelers, is considering posting subscriber reviews on his website later this year.

Now, with a social networking feature that launches today, major player TripAdvisor is addressing a key concern about mass-market review sites: How, skeptics say, do you trust a praise or a pan when you don't know the author's credentials and tastes?

Get the full story at USA TODAY