If the Justice Department does allow Google to serve ads on some of Yahoo's websites, Wisconsin Senator Herb Kohl believes it should then monitor "the amount of advertising outsourced by Yahoo to Google" to make sure it doesn't increase over time. His math: "Should the amount significantly increase, we believe the threat to competition will also increase." Then, the DOJ could step in "if, over time, you determine that Google is gaining a dominant market position as a result of the Google-Yahoo agreement." Here's hoping Alaska Senator Ted Stevens will weigh in next on the need to monitor the deal's tube-clogging effects. [Reuters ]