In the space of two weeks, online retailer Amazon.com has been forced to apologize, issue refunds and appease angry customers after being found to have charged some people higher prices than others for the same items.

With the virulent reaction of Internet-savvy customers and Amazon.com's rapid decision to drop what it called "random-pricing tests," other online retailers will now think twice before offering different prices to different customers.

Amazon.com has faced allegations -- which it denies -- that the varying prices were based on customer data it obtained via software interactions with shoppers as they visited its site.

Such data could include a person's address and how much and what he or she might have previously bought at Amazon.com.

"We've never tested and we never will test prices based on customer demographics," founder Jeff Bezos said in a news release late Wednesday.

Setting prices based on a shoppers' income level or buying habits is known in the retail industry as "dynamic pricing."

In well-off neighborhoods, for example, department stores often charge more for the same goods than in outlets in poorer areas.

The Internet, of course, is different. The vast databases of Internet retailers like Amazon create the possibility of targeting prices directly to individuals, based on their billing information and purchasing history.

Software tools available to online retailers allow them to compile sophisticated dossiers on surfing habits of customers on their sites. Through such tools, Amazon.com and other e-tailers learn customer preferences and target individual shoppers with customized screen offerings.

Amazon denies using such information in setting the different prices for different customers.

And because of its experience as bellwether of the online retailing industry, e-tailers in general may never get the chance to do effectively practice either random or dynamic pricing.

People who shop on the Internet have proven to be sharp-eyed -- with the Net itself encouraging comparison shopping and swapping of information by consumers.

Besides, unlike their bricks-and-mortar counterparts, online retailers only have one store.

"With popular sites like Amazon, you really can't get much past the consumers anymore," said Tom Wyman, electronic commerce analyst for J.P. Morgan. "They're out there trading notes all the time, looking for the best deals."

Amazon first ran into trouble a few weeks ago when some customers who bought digital versatile disc movies began comparing notes on online discussion boards.

News media picked up on the disparity and Amazon.com then said it had been conducting random pricing tests -- randomly offering the same DVDs at different prices to different customers.

Amazon.com spokesman Bill Curry said the tests were useful in determining a price point -- the right balance between how much Amazon.com could charge and still maintain a good sales volume.

Nevertheless, because of the consumer outcry, Amazon.com ended up refunding 6,896 customers an average of $3.

Amazon.com has no immediate plans for more random testing, but Curry wouldn't rule it out in the future. He said customers involved in any test would get a refund if they paid more than the lowest price used in the test.

Such pricing tests have privacy advocates concerned, since consumers have only a company's word and their own observations that personal information isn't used.

"Certainly, the Internet is wonderful for trading information for consumers," said Jason Catlett, president of the advocacy group Junkbusters. "And, Amazon.com is under a tremendous amount of scrutiny. But until the U.S. adopts laws protecting the use of consumer information, many of these companies won't get caught misusing this data."

The U.S. Federal Trade Commission did step in this summer to urge online advertisers including DoubleClick not to invade people's privacy by using personal information to individually match customers with advertisers or product offerings.

The FTC also restricted the defunct toy retailer Toysmart.com as it tried to sell off its customer lists.

Wyman said Amazon.com's misadventures may help to prevent widespread use of such practices.

"Most e-commerce sites right now need to charge as close to the suggested retail price as possible. They need the money," Wyman said. "I think the days of deep discounts are done. And dynamic pricing really only works online when you're below the normal retail price."