Kind of pointless
Yahoo has been foundering about for years now. Totally directionless while halfheartedly trying to add me-too social media functions. They basically gave up on search, gave up on being a directory, and now hang on mostly out of the momentum of people over the years who use their free web email accounts, which Google is now chipping away at with the superior Google mail.
She's no doubt a smart girl/woman now looking squarely into the mouth of middle age and eventual retirement, so she has to be doing her spreadsheets on how to maximize her earning potential to provide for herself and her offspring. She has also concluded that she has no further promotion opportunities at Google, so why not take the position at Yahoo. She finally gets to be the big cheese with the best parking spot, office and perks and only has to suck up to and charm a board, who most typically are completely clueless and more often a simple challenge of massaging overblown egos once a month.
She has never impressed me as the vision type, more the office politics corporate ladder climber, so other than cementing her political house within Yahoo staff and board, I doubt she will make any significant improvement to Yahoos value. Yahoo lacks vision, they simply have no clear objectives.