Following suggestions that Microsoft might be better off selling Bing, The New York Times takes a closer look at the search engine. "Microsoft's assault on Google in Internet search and search advertising may be the steepest competitive challenge in business today," the paper writes. "It is certainly among the most costly." Indeed, trying to take on Google costs Microsoft upward of $5 billion a year, writes NYT, citing estimates from industry executives and analysts. Since its debut two years ago, Bing has steadily picked up traffic, accounting for more than 14% of searches (30%, including the searches Microsoft …