Question: What are the best question-and-answer sites?

I've somehow developed a reputation for being knowledgeable. Intruth, it's just that I know whom to ask for help, includingInternet sites where smart people share their expertise free ofcharge.

That's the winning secret of the vast online reference workWikipedia. But it also drives a number of online services called"Q&A" sites, where people post questions and count on fellowInternet users to serve up useful replies.

The new Q&A site Quora.com has already become famous for its high-quality answers and high-profile users. Ask a question at Quora, andthere's a good chance that AOL founder Steve Case or the cofounderof Facebook, Dustin Moskovitz, will provide the answer.

Facebook itself has joined the fun with a new Q&A feature that'spresently available to a limited number of users, as the companyworks out the bugs. Then there are lower-profile services such asAardvark and Fluther, and of course the favorites, Answers.com andYahoo Answers, which have been helping kids with their homework foryears.

All Q&A services are easy to use. Just log in and type aquestion. Most services allow you to assign a topic category,ensuring that your questions will be seen by people who know aboutthat particular topic. Your question about, say, Winston Churchillcan be aimed directly at British history buffs. Or you can publishthe question to all users and hope for the best.

But "the best" can vary considerably. Answers.com, for instance,combines responses from ordinary Internet users with high-qualityinformation from standard reference works like Wikipedia, theEncyclopedia Britannica, and the American Heritage Dictionary. Formany simple fact-based queries like "What's the capital of NorthDakota?" you'll get an instant answer.

Most Q&A sites also deliver fast answers by looking up questionsthat have already been asked. As you type your question, theyinstantly begin to search for similar queries posted days or monthsearlier. If you're lucky, the answer is already there. That worksfine at sites like Yahoo Answers and Answers.com, which have storedmillions of answers. But at the newer sites, like Quora and FacebookQuestions, even simple queries - like the capital of North Dakota -may not be on file yet and can go unanswered for hours or days.

Don't expect canned answers from Aardvark, an interesting Q&Asite owned by Google Inc. Aardvark, located at www.vark.com, callsitself a social search engine. Your questions are sent directly topeople who claim expertise in the field. Conversely, you're askedwhat your areas of expertise are, and questions on those topics aredirected to you. There's a risk that the answers will be slow incoming, but not for me. My questions on Nikon cameras, Internetaudio streams, and quarterback Brett Favre were all answered withinminutes. Did you know there are at least three companies that makeflash units compatible with Nikon's high-end digital cameras? Meneither, but I do now.

Still, answer quality is a problem for all Q&A sites. Lots ofreplies are unhelpful or just plain wrong. Q&A services use a numberof quality-control tactics. For instance, at Yahoo Answers, newusers can post limited numbers of questions and answers. But theyget points for giving good answers, and the more points theycollect, the more questions they can post. People who consistentlyprovide dumb or insulting answers get negative ratings that limittheir access to the service.

Quora is even more aggressive. It requires members to use theirreal names. You can fake it, but if site operators get suspicious,they can demand proof of identity or kick you out. Also, correctspelling and punctuation are mandatory; leave out a question mark,and your question gets blocked.

During its start-up phase, Quora was available by invitationonly, and most invites went to prominent tech-industry leaders likeCase. That's why Quora's answers on all things digital tend to bequick and reliable. A question about Microsoft software was answeredin minutes. But it was two days until I got a good answer to myquestion about Sunday's NFL playoff game between the Bears andPackers.

Even Quora executives admit that they're worried about retainingthe site's high quality now that anybody can join. But it'sprecisely the ability to seek out answers from millions of Internetusers that makes Q&A sites so useful, and helps technologycolumnists pretend that they're smart.

Hiawatha Bray can be reached at bray@globe.com.

SEEKING ANSWERS

Hiawatha Bray gives a tour of some popular question-and-answerwebsites at www.boston.com/business/technology.

20techlab.ART