Yahoo: new boss - FT.com It is probably Warren Buffett's most-quoted aphorism, with good reason: "When a business team with a reputation for brilliance tackles a business with a reputation for bad economics, it is the reputation of the business that remains intact." This timeless insight (which is after all just a dolled-up version of the old point about sow's ears and silk purses, and other, less printable adages) will be the second thing that passes through many people's minds after they hear that Yahoo has hired Marissa Mayer to be its next CEO. The first thing will be: nice job, Yahoo. It is very difficult to imagine that Yahoo could find a much stronger candidate for the job. She has been a crucial part of Google's team since the search company's early days. She most recently ran its local search and maps businesses, and has had a leading role in developing several other key products. This is a coup. It is also very difficult to see how a great leader could make much difference at Yahoo, given its weakening position in the internet advertising market. Its share of the US display ad market will fall to 9 per cent this year, half the level of four years ago, according to eMarketer; the decline in its share of the search business, to 12 per cent, has been even more precipitous. The company did generate $865m in free cash flow over the past 12 months, and has $2.5bn in cash on the balance sheet, with several billion more to come when the proceeds of the Alibaba stake sale come through. If there is one thing we know about the consumer internet business, however, it's that it is very hard to reverse share losses (just ask Tim Armstrong, the brilliant Google sales executive who has been trying to turn around AOL, about this). And if it were possible to buy one's way to internet relevance, every legacy media company would have a leading position in that space.