Trademark issue

InfoWorld: " Google has never had to undertake this process. The company's trademark policy on ads puts the onus on trademark owners to complain to Google about potential violations, not on Google to proactively screen its ads for possible infringement. Google's current policy, revised in April 2004, allows trademark keywords, and pledges to investigate complaints only when trademarks are used in the ad text itself"

Eventually this has to be sorted at the global scale. Trademarks, Keywords and Tags are going to get mixed up in this search driven billion dollar game.