Bit by bit, Marissa Mayer’s Yahoo strategy gets clearer

February 13, 2013, 1:48 PM UTC

FORTUNE — It’s hard to blame Marissa Mayer for speaking in platitudes and vagaries, though she’s now seven months into her reign as Yahoo’s CEO. With apparently successful revamps of both email and the Flickr photo service already under her belt, she’s now focused on strategies for other services, including search and mobile apps.

Much of her Q&A session during the Goldman Sachs (GS) Technology and Internet conference on Tuesday mirrored what she said during the company’s fourth-quarter earnings call a couple of weeks ago: Her main areas of focus — the “big four” — are search, display ads, mobile, and video. About the only news she made was to say that Yahoo (YHOO) plans to reduce the number of mobile apps it offers down to 12 or 15 from about 60 now. The current, bloated offering makes for “a very scattered product portfolio,” she said. Some apps will be merged together, others will continue to stand alone, and whatever remains will be discontinued.

While she reiterated that mobile will make up a big part of Yahoo’s future, she made no pretense that she has the revenue model worked out. But she also noted that no other company has it figured out either. She operates on the (probably accurate) presumption that where users go, revenue will surely follow. For now, she said during the earnings call last month, revenues are “nascent.” But with 200 million unique monthly users for Yahoo’s mobile apps, there is enormous room for revenue growth. Most people, she guessed on Tuesday, will choose two to four apps “that matter most” to them.

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She was less precise when discussing the other three of her “big four.” Search and display ads, where Yahoo trails Google (GOOG) by a considerable margin, will be driven by “personalization,” though she didn’t outline a detailed strategy. Content is another driver, though Mayer has indicated that her main focus will be on services. “Overall,” she said, “we have a commitment to bringing excellent content to users, that’s what people have come to expect on the Yahoo homepage, sports, and others.” She also mentioned content partnerships, which served to underline her emphasis on services. Don’t expect any new original-content plays from the company.

In particular, don’t expect any new forays into music, though partnerships are a possibility. “I don’t think we’re going to pursue music ourselves,” she said. “As we look for the innovative and differentiable angle, I don’t think that’s an area [where] we see a lot of opportunity.”

Opportunities lost (before she arrived) made up much of her presentation. She won’t do music. She won’t add much if any new content. She won’t do maps (“because I know from my past life” — as a Google executive — “how expensive that is”). On the other hand, everybody had written off Flickr as a lost opportunity, but since the revamp, 25% more photos have been uploaded to the service.

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Another opportunity blown by previous regimes is video. Here, though, Mayer seems to think the company has a shot — though details are scarce. It “is going to be very important to our strategy,” she said. It might still take a miracle to turn Yahoo around, but she’s at least made a good start, and investors seem to agree. The company’s stock has risen by 36% since she took over last July.