Search me: How did Google become the world's most valuable brand?

In its recent "BrandZ 100 Most Valuable Global Brands Ranking," Milward Brown Optimor, a market research company, declared that Google (GOOG) is the most valuable brand in the world. Citing a valuation of just over $100 billion, the ranking placed it ahead of Microsoft (MSFT), Coca Cola (KO), IBM (IBM), McDonald's (MCD) and dozens of other internationally-recognized favorites.

Milward Brown's valuation is based on the revenues that it assumes the companies will earn over the course of their existence. In this context, the valuation of Google is particularly interesting. As ubiquitous as it has become, the search behemoth doesn't behave like most mega-brands. Unlike Coke or Tide or Lucky Charms, it doesn't sell tangible products.