Microsoft's (Nasdaq: MSFT) two-year cashback experiment is over. The world's largest software company is ending its loyalty shopping program, where folks who shopped through Bing-affiliated e-tailers would receive a small chunk of their purchase back in the form of cash rebates.

Many leading media voices didn't like the idea, calling the move desperate bribery. But I warmed up to the idea. Savvy online users flock to websites that give them a little something for the things that they were going to do anyway:

  • OpenTable (Nasdaq: OPEN) enhances its online restaurant reservations site by providing points that build toward eatery rebates.
  • Amazon.com (Nasdaq: AMZN) encourages websites to promote its product by offering webmasters and bloggers a piece of the action through its Amazon Associates affiliate marketing program.
  • United Online's (Nasdaq: UNTD) MyPoints rewards shoppers who go through its sites for their e-commerce needs. Points are traded in for gift cards good at many of its retail partners.

Microsoft's cashback platform wasn't bribery. It's perfectly reasonable to incentivize your user base. Google (Nasdaq: GOOG) never had to do that as the top dog, but maybe that's why Froogle -- eventually rechristened with the blander moniker Google Product Search -- has never really taken off the way it should have.

"For merchants and advertisers, we have some ideas for making it easy to get a broader array of products and offers into Bing, and we'll share some details on this later this summer," reads Bing's official explanation.

What about the consumers? When the program comes to a close next month, regulars may actively avoid Bing's product searches, because they may feel they're being cheated. They grew to approach Bing-enabled purchases as the means to building something, just like they would with many rewards-based credit cards. JPMorgan Chase (NYSE: JPM) has inundated the ad market with its spots for the Chase Sapphire rewards card.

Rebates work. They're not entirely necessary, but it's hard to turn off the spigot after it's been running for awhile. 

Did you ever use Microsoft's cashback or any other online loyalty program? Share your experiences in the comment box below.