Credit: Yahoo

Want proof that most investors are short-term obsessed? Earlier this week CNBC ran a story about Yahoo (NASDAQ:YHOO) stock falling 6% so far this year because shareholders are "spooked" by rumors that CEO Marissa Mayer would pursue ill-advised acquisitions.

Two things here. First, can we please remember that Yahoo stock has more than tripled since the beginning of Mayer's reign? And second, we're just 15 days into the new year, people. Fifteen freaking days. If you're freaking out about any of your holdings falling 6% over two weeks -- or even a few hours -- you shouldn't be investing in stocks.

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The only question worth asking here is whether Yahoo stock can continue to beat the market over the next 3-5 years. I think it can. Here's why.

The mobile opportunity is massive
A bad search deal with Microsoft coupled with a weak display advertising market has held Yahoo back for years. That's still true, but the tide is turning.

In Q3, Yahoo for the first time reported that search and display revenue from mobile apps and devices exceeded $200 million -- a "material" result. For the full year, Mayer and her team are targeting at $700 million in GAAP revenue from mobile sources. An impressive result when you consider that analysts are expecting Yahoo to report $4.4 billion in 2014 revenue after traffic acquisition costs. (The company will announce fourth-quarter and full-year results after the bell on Jan. 27.)

And yet Yahoo's mobile momentum shouldn't be surprising. The company's apps are enjoying strong support among users. Take Yahoo Weather, one of my personal favorites. The iOS version nabbed an Apple design award last year and gets 4.5 stars out of more than 93,000 ratings. The Android version nets 4.4 stars from over 711,000 ratings.

I've also come to depend on news notifications from the Yahoo app on my Android phone, use Yahoo Sports for fantasy football, and have Yahoo Finance as one of a handful of go-tos for tracking stocks on both my phone and my iPad.

Many more like me are out there. Yahoo reported 550 million mobile active users in the third quarter, up an estimated 17% over the past year. That's strong growth which, given time, should more than compensate for weakness in other areas.

Content is king, and Yahoo is getting more of it
Yet Mayer isn't stopping at mobile. She and her team have made and continue to make big investments in original content and programming, including bringing back the cult hit Community for a sixth season. New episodes will become available March 17 on Yahoo Screen.

Other moves include the new digital magazines Yahoo Tech, Yahoo Style, and Yahoo Health, among others, and hiring well-known celebrities for original programming. For example, Katie Couric hosts a regular news show as Yahoo's "Global News Anchor".

These initiatives come as the lines between traditional and online media continues to blur. At Sunday's Golden Globe awards, two streaming-only programs earned top awards from the Hollywood Foreign Press. Amazon.com's Transparent won for best musical or comedy with star Jeffrey Tambor taking home the Globe for best performance by an actor in the same category. Netflix's House of Cards also scored with Kevin Spacey nabbing best performance by an actor in a drama series. Yahoo is investing in a market that's ready for more edgy and interesting digital programming.

How Alibaba plays into it
Finally, I need to point out that -- thanks in part to its huge stake in Alibaba (NYSE:BABA) -- investors buying now are getting at least $32.12 a share in tangible book value, according to S&P Capital IQ estimates.

What that means, simply, is that roughly no less than two-thirds of Yahoo's present value is denominated in cash, held investments, and other assets that can be liquidated. Growth isn't part of the equation. Is that fair? I suppose it would be were there no hope that Mayer will bring back growth, and yet the numbers above paint a different picture.

Meanwhile, the key executives betting on Yahoo's future have plenty to lose if they're wrong. Co-founder David Filo returned to the board of directors last year and remains the company's largest single investor with about 7.5% of the shares outstanding. Mayer, too, has a sizable stake with 2.3 million directly held shares and another 3.18 million in to-be-exercised stock options.

Yahoo stock may be down slightly year-to-date but it's way too soon to count this business out. If anything, the transformation that Mayer promised upon joining the company in 2012 is just getting started.

Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team and the Motley Fool Supernova Odyssey I mission. He owned shares of Apple and Netflix at the time of publication. Check out Tim's web home and portfolio holdings or connect with him on Google+Tumblr, or Twitter, where he goes by @milehighfool. You can also get his insights delivered directly to your RSS reader.

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