1) Silicon Valley is Booming again and there has been a lot of job growth in companies such as Zynga, Facebook, and Google
2) There is a large number of people looking to live in the Bay Area and there is only a limited amount of land available
3) There are a lot of great universities such as Stanford and UC Berkeley where academics, researches, and alumni launch start up companies
4) Napa Valley and the wine region
5) Geography with bay views, hiking and outdoor activities which people like