But you know the sad saga: As more and more travelers began to accumulate and redeem miles, the airlines began to realize that they were losing money. They were giving away seats to freeloaders when they could be filling them with full-fare customers.

And so the airlines began to impose restrictions on their mileage programs. You couldn't use miles to get seats around Christmas, New Year's Day, Thanksgiving or Easter; you couldn't use them to fly during peak summer periods. You needed to book flights weeks and sometimes months in advance; and fewer and fewer seats on each flight were allocated to passengers flying on free tickets.

Then the miles began to come with expiration dates, like milk cartons: "Do not use after ..."

Soon, keeping track of your miles almost became more of a hassle than they were worth. You'd look at your statement and think, "I'm about to lose my miles. I'd better fly somewhere quick." Or even more sobering: "If I just fly to Salt Lake City this weekend, I'll have enough miles to get a free ticket."

Tim Olson saw this dilemma as an opportunity.

Seven years ago, Olson had been working in the bank card industry and wrestling with a different problem: Banks wanted to add mileage components to their credit cards, but there were more banks than airlines, so some banks were being locked out of the airline programs.

Then he hit upon a solution that solved both frequent fliers' and banks' problems at once: Why not create a generic miles program that wouldn't be tied to a specific airline? There had been some stabs at the problem by credit card companies like Diner's Club, but they were still often subject to the same old limitations.

As Jennifer Case, vice president of marketing for WebMiles , explains: "Tim knew that people will do crazy things when they are offered miles -- it's a powerful way to change consumer behavior and to build customer loyalty. He just adapted the program so that consumers wouldn't have to deal with all the restrictions.

"Then, as he watched the Internet take off, he recognized the clear and growing need for e-tailers to retain customers, and he saw frequent flier miles as the perfect way to inspire customer loyalty.

"So he got together with e-commerce strategist Jeff Crapo and they launched WebMiles on Jan. 17 of this year."

The first few months were quiet as the company built up a network of partners, but in June and July WebMiles leaped into the public swimming pool with a nationwide advertising campaign promoting its new MasterCard and proclaiming its core customer promise: Any airline. Any flight. Anytime.

"Any airline, any flight, anytime" sounds great, but how does it work?

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