If history proves anything, it's that leadership matters. In government. In military affairs. In education. And certainly in business. Think of how bringing back Steve Jobs helped turn around Apple (NASDAQ:AAPL). Or how Elon Musk has stiff-armed skeptics on the way to creating billion-dollar companies in Tesla Motors (NASDAQ:TSLA) and privately held SpaceX.

Then there's Marissa Mayer, the former Google executive who's brought equal doses of enthusiasm and controversy to Yahoo! (NASDAQ:YHOO). Employees love her for the most part, and for good reason, says Tim Beyers of Motley Fool Rule Breakers and Motley Fool Supernova in the following video.

Thanks to moves aimed at profiting from the rising use of smartphones and tablets, Yahoo! has seen its stock roughly double the market's return year to date, and it's up nearly 50% since Mayer joined the company last July.

Tim says to expect further gains. Do you agree? Please watch the video to get his full take, and then let us know what you think about Mayer's strategy in the comments box below.

Fool contributor 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 Google 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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