Microsoft is now offering frequent flyer miles to frequent users of its Live Search tool in the US - but only if they surf with Internet Explorer: Users of Firefox, Chrome or Safari are out of luck.

Frequent flyer miles with companies including American Airlines, Delta and US Airways are just some of the perks Microsoft is offering in a new reward programme called SearchPerks.

The company desperately needs to attract eyeballs to its search sites, as it is continuing to lose market share to Google. In August, 63 percent of US searchers turned to Google, up from 61.9 percent in July, according to figures released in mid-September by comScore, a tracker of online trends. In the same period, Microsoft's share of the search market dropped 0.6 percentage points to 8.3 percent, while Yahoo's slipped 0.9 percentage points to 19.6 percent.

Following the collapse of its plan to buy search market share through a merger with Yahoo, Microsoft has been looking for other ways to boost traffic to its online properties.

Back in May, it started paying rebates to US users of its comparison shopping service to generate more traffic on the site. Live Search cashback was based on, a company Microsoft acquired in 2007.

Following its acquisition of European comparison shopping service Ciao in August, Microsoft expects to take the cashback programme across the Atlantic next year.

For now, the rules of the SearchPerks programme restrict it to US residents.

With a Windows Live ID and a piece of software downloaded from the SearchPerks site, users of Internet Explorer 6.0 or later can collect a virtual ticket for each search they make, up to a limit of 25 per day, and exchange the tickets for miles or other prizes. Including a 500-ticket sign-up bonus, it will take them over three weeks to win a T-shirt and almost four months to win a cookery book through the program.

Registration is open until December 31 and is available to the first million users to sign up. Anyone with their eye on the top prize, an Xbox game controller, will have to hurry: the game ends on April 15.