Microsoft's Cashback service didn't work out, but the company is still experimenting with the concept of repaying users, this time with a program that rewards people for searching on Bing.

Bing Rewards offers users credits for using the search engine and allows people to redeem the credits for a variety of products. To get started, users download the Bing Bar and sign into the Bing Rewards program with their Windows Live ID. The Bing Bar displays offers that let users earn credits and also counts users' credits.

People earn credit in a variety of ways based on offers that pop up in the Bing Bar. Ways to earn credit include searching on Bing, setting Bing as the default search provider in the browser or trying new Bing features.

Microsoft offers rewards to users for searching on BingSigning up nets a user 250 credits, which buys the cheapest item in the program. There are a variety of items people can buy with the credits, such as DVDs, cookware, restaurant gift certificates, digital cameras and luggage.

People can use their credits to make donations to select charities, with 100 credits equaling a US$1 donation. Credits can also be exchanged for Microsoft Points to make Xbox and Zune purchases.

The program is only available in the US and Microsoft is calling it a "preview," although it appears available to anyone who wants to sign up.

The launch of Bing Rewards follows the closure of Bing Cashback in late July. Cashback offered online shoppers cash rebates for buying products after searching for them on Bing. When announcing the shutdown, Microsoft said the service didn't get the broad adoption the company had hoped for.

The idea of rewarding users for searching on Bing is one that Microsoft founder Bill Gates seemed particularly interested in. Before stepping down from his leadership role at the company, he often spoke about the idea of giving people a reason to use a particular search engine.

Since launch last year, Bing has steadily if slowly gained market share. By August this year, Bing had grown its search market share by 30 percent over last year, to 13.9 percent, according to Nielsen.