Now that Marissa Mayer has invested at least $200 million to buy up as much mobile engineering talent for Yahoo as possible, she's certainly not going to neglect her new, very important hires. In her quest to spur a Yahoo "renaissance," as she calls it, Mayer has decided that the company will focus on the inevitable future of smartphones. "I hope that at some point we are looking at a world where mobile is a majority of our revenue," Mayer told Bloomberg Businessweek's Brad Stone.

That, so far, has meant acquiring 18 companies just to add their engineers to build up the current 330 engineers on the mobile team, which has cost her at least $200 million, according to Stone. (That doesn't include the $1.1 billion she spent on Tumblr.) When she got to Yahoo, the group only had a few dozen engineers. With each of those buys, Yahoo has locked in those people with 2 to 4 year contracts so that they can build apps and hire bigger teams, sources told Stone.

Despite getting a bunch of money, not all are excited to have landed at Yahoo. "I was really worried," Josh Schwarzapel, a senior product manager for mobile whose video chat startup OnTheAir was acquired by Yahoo for an undisclosed amount in December told Stone. "I had a lot of friends who came in [to Yahoo] and were rejected by the host." So, Mayer has gone to great lengths to make these people feel accommodated. She has renovated the Sunnyvale work space and she gives the team special attention with regular meetings and product reviews. 

Her strategy has started to work, with the company putting out two very popular mobile apps — Yahoo Mail and Weather. But she finds herself unable to make money off of these popular creations — while competitors like Facebook wow investors with mobile revenue. So far, most of the company's recent good fortune has been due to its stake in Chinese e-commerce portal Alibaba while its own advertising revenue is down. 

Mayer she sees herself as more of a Sarah Hughes, the Olympic winning figure skater who won the Olympic gold only after everyone else messed up their routines. "No one thought Sarah Hughes had a chance to win," she told Stone. "Afterward, Hughes said that she didn’t quite know how she had done it," Mayer says, "and she wasn’t sure she would ever be able to repeat it. It was the routine of her life." So, the game plan is to hope everyone else flubs just enough for Yahoo to come ahead, then?