Corporate Noise Machine

Google recently announced the appointment of Ms Shirley Tilgham Ph.d to the Board of Directors. She is also President of Princeton University and a Professor of Molecular Biology. The press release outlines her very substantial accomplishments in molecular biology and how Google is research based etc etc.
Come on Google. Why do you need a renowned professor of molecular biology on your board? Assuming this is a good appointment, and it probably is, perhaps its her connections as President of Princeton that make her attractive, including access to pools of capital and government contacts.
This raises the issue of Boards of Directors accountability and suitability. Does a deep and impressive background in molecular biology provide the necessary context to manage the corporate governance of Google. Or is she expected to wheel and deal as many corporate boards of directors are expected to. In that case who is watching the shop?