Online retailer Amazon on Thursday launched in public beta its question-and-answer Web site that lets users share knowledge with each other, and offers rewards to those who consistently provide quality information.

Askville.com has been available to a select number of users since it was first launched in beta in December 2006. The current version is open to everyone.

The concept behind Askville.com, which is similar to Yahoo's Answers, is to have users respond to each other's questions, which are posted on the site.

Tapping human knowledge directly fills in the gaps left from automated Web search engines. Not all questions can be answered through an Internet search, Amazon said. "Plus, it is a lot more fun interacting with real people versus looking at a list of Web site links from a search engine," Joseph Park, director of Askville.com, said in a statement.

It may be fun, unless a person is looking for an answer right away. Responses are not always immediate with such Q&A sites.

Amazon is not new to search, an area in which it hasn't excelled. The company launched its own search engine A9.com about four years ago, and then decided in October 2006 to scale it back, eliminating many of its most interesting capabilities. Among the features to go was its mapping technology that captured street-level images of businesses in major U.S. cities. Today, the site is strictly e-commerce, focusing on product searches on Amazon.com and other retail sites.

Amazon.com believes Askville.com is a good idea, because a quarter of all questions asked on such sites are shopping related, such as "what's the best mountain bike," Park told InformationWeek. While respondents can recommend any retailer they wish, Amazon.com has added a shopping widget that makes it easy for someone to see if the site offers the product. "They actually enjoy recommending products," Park said of Askville users. "It has almost become a game to our users."

Askville.com is available to any Amazon.com customer. Non-customers and customers can use the service through their mobile phones. People who provide quality answers on a regular basis will be rewarded with Quest Gold, which initially can be redeemed for Askville.com T-shirts and coffee mugs. For a limited time, Amazon will offer people who prove to be experts in a field a $100 or $50 gift card that can be used in buying products through the retailer.

Amazon plans to launch a branch site of Askville.com called Questville.com, which people can use to redeem their Quest Gold. Amazon plans to increase the number of rewards.