Cashback is a Microsoft Live Search offering that gives money back to people who search for and buy products from retailers that participate in the program.

The new "instant cashback" feature delivers rebates to eBay shoppers immediately, rather than after 60 days. It works for people who buy products through the cashback program and pay for them using PayPal. The feature is only available to certain "eligible" users, as determined by eBay, according to a spokeswoman with Microsoft's public relations firm.

The instant feature, announced Monday on the , follows a rough day for the service on Friday, one of the busiest shopping days of the year in the U.S. The Cashback site was down for several hours on Friday, Microsoft said.

The downtime happened while Microsoft investigated a problem and rebuilt the databases that support Cashback, the company said.

In addition, some people hoping to take advantage of a promotion that offered a 40 percent discount on some Hewlett-Packard products purchased through Cashback reported getting instead. In a statement, Microsoft did not directly address why that happened but said people who completed the purchase of an HP item and should have gotten the 40 percent discount should contact Microsoft . Those buyers will have to provide their order number and the e-mail address they provided during the buying process.