NEW YORK - Had Jani Patokallio relied solely on a printed travel guidebook to plan a recent trip to Cambodia, he might have skipped a visit to Sihanoukville, turned off by talk of bumpy bus rides, bombed out buildings and kidnappings.
After checking out Wikitravel, one of several free sites that let travelers share information and reviews, he learned the seaside town has changed since the book's printing.
"Five years ago, it was absolutely nothing there," said Mr. Patokallio, 29, a telecom consultant in Singapore. "Today, it's already a beach resort. There are five-star hotels, good restaurants. The road is paved and rebuilt."
When he got back, he added his experiences and insights, expanding the entry by 50 percent, so that other travelers might consider a visit, too.
In the old days, travelers had to rely primarily on professional guidebooks, unless they happened to know someone who has gone to, say, Sihanoukville recently.
These Web sites make it possible to find that person who did visit Sihanoukville. Several new ones have emerged in recent months, selling their ability to stay current and cover destinations popular and obscure, even as guidebooks respond by emphasizing their editorial oversight.
Internet Brands Inc.'s Wikitravel and Wikia Inc.'s World Wikia organize user contributions the way a traditional travel guidebook would, with sections on how to get there, what to eat, where to stay and what to do. Powered by technology known as a wiki, anyone can add and change entries, regardless of expertise.
Gusto LLC, IgoUgo Inc. and other travel sites take more of a social-networking approach.
Members have personal profile pages just like those on News Corp.'s MySpace. Visitors not only can read what others have to say but also can find out about the reviewers' background: Do they travel with pets or kids? Do they tend to like destinations that are off-the-beaten path?
TripAdvisor LLC, meanwhile, offers a blend of wikis and profiles.
One site, Tripmates Inc., even lets people find travel companions or contact locals for one-on-one advice. Joe Voboril, 28, a financial analyst in New York, contacted a Tripmates user in Greece who had highly recommended a sunset cruise that from guidebooks "looked like a touristy, dumb idea."
"It was one of the best values," he said. "I never would have done it or looked for it."
RealTravel Inc. has a tool for recommending travel destinations based on criteria you enter, such as budget, age, interests and the size of the traveling party. Matches are made based on what similar users have said about places they've been.
Frommer's, Fodor's and Lonely Planet typically hire locals and seasoned travelers to update their guidebooks every one or two years. Although the publishers acknowledge that their paid writers can't cover every single restaurant or hotel, the way scores of volunteers can, they question whether travelers really want everything.
"There's so much information out there that people want somebody to discriminate for them," said Michael Spring, the publisher of Frommer's Travel Guides, a division of John Wiley & Sons Inc. "We're not doing anyone a favor to list 100 places. You want someone to say this is better than that."
The philosophy extends to the guidebooks' Web sites. Lonely Planet Publications Inc. has a lively online forum for discussions about everything travel, but when it comes to reviews, the publisher wants readers to respond only to items written by professional writers.
"That's who we are, and people look to us for that impartial review," said Brice Gosnell, Lonely Planet's publisher for the Americas.
Lori Gauld, 34, said she likes RealTravel for its journaling features but prefers guidebooks for planning trips.
"I write all my notes (and use) Post-its, highlighters and things like that," the Toronto consultant said. "I can bring the book along."
Reviewers' credibility is one concern. Sites differ on how they handle hotel owners, tourism officials and others who might want to flood the sites with positive reviews, but all agree it's a potential problem.
The Web sites, meanwhile, are good for niche travelers and destinations that a travel guidebook might not mention.