A lot of companies are using the brand names of their competitors products and services for sponsored advertising on Google. In some cases this completely legal, but in many cases it can lead to a Trademark Infringement action. I’ve worked successfully on both sides of the issue, helping clients enforce their trademark rights against competitors, and helping other clients craft AdWord creative that doesn’t cause consumer confusion leading to charges of infringement.
This body of law is evolving, so it’s important to stay on top of the current standards.
Call me or email if you need help figuring out where you stand.