Microsoft (Nasdaq: MSFT) has spent a lot of money on Bing's marketing campaign. Now it's willing to dig a little deeper to make sure that you -- yes, you -- are using it.

Microsoft is rolling out a beta preview of its Bing Rewards program.

"Become a member of the Bing Rewards Preview and experience the benefits of doing what you love to do online -- learning, discovering, exploring -- while getting opportunities to earn credits toward great rewards," reads the pitch.

Participants simply download the Bing toolbar, earning points through offers that include things as simple as relying on Bing for search queries to making the engine your homepage. The toolbar is there to keep you honest.

A desperate move? Not so fast. Many respectable companies have gone this route. Sure, Google (Nasdaq: GOOG) and Yahoo! (Nasdaq: YHOO) never had to bribe their bases. Amazon.com (Nasdaq: AMZN), on the other hand, did exactly that.

When Amazon was trying to get its fledgling A9 search engine off the ground, it offered active users a small discount on its namesake e-tail site. The 1.57% -- half of pi (nerds!) -- discount was discontinued two years later.

Loyalty programs are certainly credible. United Online's (Nasdaq: UNTD) MyPoints offers users points for taking surveys and primarily buying stuff from its affiliate merchants. Those points can be exchanged for gift cards.

Freebies sell. Surely you've seen one of the many JPMorgan Chase (NYSE: JPM) ads with the precocious couple making the most of the Chase Sapphire rewards program.

Heck, even Microsoft played this card. Its Live Search Cashback loyalty shopping program had a two-year run. If it were a dud, I doubt that Microsoft would give it another go.

If Microsoft is able to pay users to use its search engine and kick off their browsing sessions on Bing, is that any different than spending on costly advertising campaigns? I don't think so.

Bing has a lot of ground to make up on Yahoo! and particularly Google. It's got a fat billfold and it's not afraid to use it.

What do you think of Bing Rewards? Share your tips in the comment box below.