According to a confirmation from Mattcutts "I’ve checked with folks at Google and they confirmed that http://too.blogspot.com/ is Sergey Brin’s blog". The word "too" in the URL reflects his life outside the work. Writing his first post on blogger Sergey mentioned that he is keen in Developing Parkinson’s Disease when he’s older which is based on the data 23andMe, a personal genetics company co-founded by Sergey’s wife Anne Wojcicki. This clearly states that Good Health is of top priority among every individual.
And the interesting point to note here is that he has Google Analytics already installed on his blog :) driving ahead with the game. Wheww thats Cool. Welcome to the world of Blogging!!!, Sergey :)