One of the things that I forgot to mention in my second talk at PubCon was that the search engines will provide you very little trademark defense if your trademark utilizes a generic term. Microsoft provides a good overview of their trademark policies on a recent post on the AdCenter blog. Note this section:
Is the term in question a “dictionary” term?
For example, if I own a window washing company and I’m bidding on terms having to do with “windows”, doing so does not put me in violation of Microsoft’s trademark for their operating systems.
Another in a long list of reasons why you should select brand names that are distinct.