Can Microsoft’s Bing, or Anyone, Seriously Challenge Google?

Every year, the market-research firm Millward Brown conducts a survey to determine the economic worth of the world’s brands — in other words, to put a dollar value on the many corporate logos that dominate our lives. Lately the firm’s results have been stuck on repeat: Google has claimed the top spot for the past three years. The most recent report values Google’s brand — those six happy letters that herald so many of our jaunts down the Web’s rabbit hole — at more than $100 billion…