Google (GOOG) is going global with an advertising strategy that has kicked up controversy in the U.S. and Europe. As part of its efforts to generate revenue from online ads, Google lets marketers in a handful of countries pay to surface their ads when a would-be customer searches for a rival's brand name.

Starting June 4, marketers in about 200 countries will be allowed to purchase rival trademarks as keywords to trigger display of "sponsored search" ads on Google. Honda, for instance, could bid to have one of its ads displayed when a consumer searches the term "Toyota." In recent years some companies have sued Google or the competing company, saying the practice is a form of trademark infringement.

Google's Rival Keyword Sales Go Wide - BusinessWeek