Marissa Mayer at CES: Will her vision kickstart Yahoo’s growth?

FORTUNE — The history of Yahoo (YHOO) CEOs giving keynotes at the annual Consumer Electronics Show in Las Vegas is not exactly stellar.

There was 2010, when Carol Bartz canceled her appearance abruptly with little explanation.

There was 2008, when co-founder Jerry Yang opened with a cringe-inducing apology. (“I’m sorry to disappoint you,” Yang told an audience that had come to see the new face of Yahoo. “It’s still the same old face.”)

There was 2006, when Terry Semel … well, no one remembers.

So the bar for Marissa Mayer, who delivered a keynote Tuesday at the annual tech gathering, was pretty low. Unsurprisingly, Mayer cleared that bar with much room to spare. She laid out a vision for the Sunnyvale, Calif.-based company that in many ways is the anti-Yang: unapologetic, fresh, forward-looking, and innovative. It fully embraces the mobile revolution and is based on four pillars: search, communications, digital magazines — more on this in a moment — and video.

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Yet it remains anyone’s guess as to whether this vision will be enough to address the biggest challenge Mayer faces: Can she restart Yahoo’s stalled growth?

Mayer spent much of her time talking about content. “Media has long been one Yahoo’s key strengths,” she said, before trotting out her marquee media hire, broadcast personality Katie Couric. (Couric, a veteran of ABC, CBS, and NBC, promised lots of interviews with newsmakers, leaders, and celebrities, but gave few other details about her plans.)

Mayer followed that by introducing Nick D’Alosio, the English teenager who founded Summly, a content startup that Yahoo bought in March for $30 million. Yahoo’s acquisition of the company, which used algorithms to summarize news stories, is controversial. On stage, D’Alosio demonstrated what Summly has become: Yahoo News Digest, a twice-a-day summary of the news that is produced from multiple sources through a blend of technology and human editing and delivered to mobile devices. As you might expect, the News Digest is heavy on photos, video, and social streams. It is meant to help people with a problem that Mayer described as “tl;dr” — Internet-speak for “too long, didn’t read.” It looks cool, but will be competing in a very crowded market.

The visually arresting look and feel of the News Digest inspired Yahoo to apply a similar presentation to other forms of content. The company asked, “What would happen if we combined the elegance of magazines with the power of the web?” Mayer said. The first result of that exploration is Yahoo Food, the first content vertical to receive the digital magazine treatment. With big interactive tiles that are easy to navigate and bold pictures, it’s somewhat reminiscent of the mobile application Flipboard.

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Yahoo also gave a magazine-esque feel to a second vertical: Tech. Another celebrity media hire — former New York Times technology columnist David Pogue, now a Yahoo vice president — took to the stage to unveil it. With some friendly digs at popular-but-geeky tech blogs, Pogue promised that Yahoo’s technology coverage would be broadly appealing and free of jargon. “Yes, it’s a magazine, but it comes out every single day,” Pogue said.

That wasn’t all. Yahoo also briefly presented on its video strategy, smart TVs, sports, and Tumblr, the social network it acquired in May for $1.1 billion. (Founder David Karp presented on behalf of that business.)

But the most important announcements, at least for Yahoo investors, came near the end. Advertising senior vice president Scott Burke unveiled a suite of new products, including an advertising exchange, and lots of “native” ads, that aim to make it easier for marketers to place ads on Yahoo properties online and in mobile.

“Our new ad products are going to make it simple for advertisers to connect directly with key audiences,” Mayer said.

It’s that promise, more than any other that Yahoo’s CEO made, that will determine the company’s fate. In the end, marketers must be persuaded to spend more on Yahoo. Otherwise, none of the considerable improvements that Mayer has delivered to Yahoo’s products during her tenure will matter.

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