Amazon.com began offering Black Friday deals today, throwing down the gauntlet to its rivals as competition for holiday spending intensifies.

New deals will be unveiled through Dec. 22 as often as every five minutes on everything from HDTVs to toys, according to the company. Amazon also is providing “curated” gift guides that it says will take the guesswork out of shopping for friends and relatives. Special offers will be available for Amazon Prime members and users of its Alexa voice control system.

“In the retail business what you are always looking for is how to get the jump on your competitors – that’s the game,” said Howard Davidowitz, the head of retail consultancy and investment banking firm Davidowitz & Associates. “Now, here is the price leader, the fastest-growing retailer in the United States -- they’re getting the jump on everybody. I think it’s brilliant they are going to capture even more market share this way.”

Amazon’s move is the latest sign of the waning importance of Black Friday -- for decades “celebrated” on the day after Thanksgiving -- as consumer spending continues to shift online. Retailers also have embraced other intra-seasonal “holidays” such as “Cyber Monday” and “Super Monday” in recent years. Even so, plenty of shoppers still spend on Black Friday, which RetailNext lists as the third busiest day of the year for brick-and-mortar stores.

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While some retailers began opening their doors on Thanksgiving Day, several chains that have done it in the past are letting their employees celebrate the holiday with their friends because the costs of opening the stores couldn’t be justified by the sales that resulted. Moreover, the additional shopping hours shifted sales that would have happened later in the month and didn’t lead to greater spending.

“People are going to spend what they spend,” said Randy L. Allen, a senior lecturer in management at Cornell University’s Johnson Graduate School of Management.

Amazon might be trying to spread out its holiday shipments into early November to avoid a repeat of the bottlenecks it experienced a few years ago which resulted in customers not getting their holiday gifts on time, according to Allen.

Shares of Amazon.com, which have been under pressure lately after the company’s recent disappointing earnings report, fell $8.75, or 1.1 percent, to $776.66 in early afternoon trading. Even so, the stock remains up about 15 percent since the start of the year, handily outperforming the broader S&P 500 Index, which posted a 3 percent gain during the same time.

Whether other retailers will follow Amazon’s lead in terms of rolling out Black Friday deals weeks before the actual Black Friday isn’t clear “because Amazon has obviously geared up to try and do this,” according to Davidowitz. A spokesperson for the Seattle-based company couldn’t immediately be reached for comment.

“What the American consumer wants is a better and better deal,” Davidowitz said. “Whoever gives it to them wins.”

Amazon consumers, though, may find even better deals if they wait.

“While it is exciting for a large store like Amazon to begin their Black Friday deals, we recommend shoppers to pump the breaks,” suggested Eric Jones of the website BestBlackFriday.com in an email to CBS MoneyWatch. “There are going to be a few gems here and there, but the actual doorbusters — the ones that people wait the entire year for — are still a few weeks away.”