Looking for a tablet this holiday shopping season? If you are, and you’re leaning towards a shiny new iPad, wait just a minute: Oprah wants you to know that she loves the Microsoft Surface. How much does the billionaire media personality love it? According to a tweet she posted this past Sunday, Oprah has already purchased 12 of the devices as gifts for Christmas.

Don’t expect Apple to lose any sleep over Oprah’s endorsement of Microsoft’s Windows 8 tablet: if you believe Oprah posted the tweet in question, she did so from her iPad.

That embarrassing fact was quickly noted by observers and widely mocked on numerous technology blogs. And for good reason: it seems quite likely that Oprah’s tweet, which follows her inclusion of the Surface on her list of 48 favorite things, was a part of Microsoft’s marketing campaign for Windows 8, making the tweet a perfect example of celebrity marketing fail.

That fail is all the more embarrassing given that Microsoft is spending more than a billion dollars on the promotion of what could be the company’s most important operating system release ever.

The cool kids

How can Microsoft convince consumers that it’s cool? Not surprisingly, the Redmond software giant has turned to the cool kids, making numerous celebrities, including Oprah, Jessica Alba, Gwen Stefani and Holly Willoughby, high-profile players in its marketing campaign. But will their involvement really pave the way for Windows 8, Windows Phone 8 and the Surface?

That isn’t so clear. Reviews of Microsoft’s new wares have been mixed, and sales appear to be far more tepid than anticipated. Microsoft is reportedly blaming OEMs, but sales of its own Surface tablet are also “starting modestly,” Oprah’s Surface gift-buying spree notwithstanding. While it would be premature to call Windows 8 and the Surface a flop, one thing is clear: Microsoft isn’t the new Apple.

Celebrity power doesn’t beat product power

That means one thing: Microsoft’s celebrity promotions aren’t going to change the game. Put simply, it’s about the product stupid. Paying celebrities to promote a product may not always be a waste of money, but it rarely makes a product.

Microsoft should have known that as there are plenty of examples of technology companies trying to use celebrity power to convince consumers that they have the right stuff. A recent example: widely-hyped startup Airtime. Founded by Napster creator Shawn Fanning and Facebook billionaire Sean Parker, the company raised more than $30m in funding pre-launch and spent some of that on a star-studded launch. An epicly disastrous star-studded launch.

Nearly nine months later, Airtime’s fate may not be sealed, but it’s safe to say that Sean Parker’s next billion probably isn’t going to come from this one.

The best promotion money can’t buy

Despite the evidence that celebrity is rarely a game-changer for tech companies, the industry continues to try to cozy up to celebrities in a variety of ways. Case in point: a former Mashable blogger and two twenty-something entrepreneurs are starting an investment firm that they hope will be funded by their Hollywood connections. While the trio says they can’t guarantee that their celebrity investors will promote the firm’s portfolio companies, given their limited experience as entrepreneurs and total lack of experience as investors, celebrity involvement is clearly what they’re referring to when they speak of “value-add.”

Of course, it’s worth noting that the highest-profile names on the consumer internet — think companies like Facebook, Twitter, Pinterest and Instagram — didn’t have to pay celebrities, or sell them shares, to get them using their products. Celebrities, like members of the public at large, were legitimately attracted to their products.

For companies looking to avoid the celebrity myth that Microsoft and countless other companies have fallen for, there’s a lesson here: the name of the game is to get lots of people using your product, not to pay a few people lots of money to to say they use it.