Marissa has been an integral part of Google's success -- she was in charge of user experience, and a wonderful job she has done. The Google search engine has changed slowly over the years -- but usually for the better. There aren't many decisions made under her watch that were wrong looking back in hindsight (though most changes are met with at least some opposition)
A new chapter in her career is about to start, as head of "location and local services". This is an extremely important area that Google is betting will bring in an ever growing amount of cash that will supplement their existing ad revenue.
To replace Marissa steps in Udi Manber -- a former Yahoo employee who joined Google in 2006. It will be interesting to see if Udi takes Google in a different direction to keep up with Bing's impressive user experience work.
What do you think? Is Google in trouble now that Marissa is gone? Or is a change exactly what Google needs?