for future reference:
One of the key reasons for Google’s success is a belief that good ideas can, and should, come from anywhere. Page and Brin insist that all engineers in the company have one day a week to work on their own pet projects. An ideas mailing list is open to anyone at Google who wants to post a proposal. What Mayer does is help figure out how to make sure good ideas bubble to the surface and get the attention they need. The task is becoming more complex as Google grows, with a workforce of 4,200 now and revenues on track to hit $3.7 billion this year.
Business Week article on Marisa Mayer