Few things: Google and Facebook have offices in New York (in the case of Facebook, there's a team available for most any engineering role in the NY office; I c

Few things: Google and Facebook have offices in New York (in the case of Facebook, there's a team available for most any engineering role in the NY office; I can't speak for Google, but I believe Spanner is out of the NY office), so for folks who really want a city lifestyle, this is always an option. As for Bay Area, the big issue are schools: San Francisco schools operate on a lottery system (with the exception of a single "test school", Lowell), whereas South Bay has excellent public schools available to all those who live within their district boundaries (Cupertino School District, Los-Gatos/Saratoga School District, Los Altos SD, several schools in Fremont area, etc...). So for many, a South Bay location is actually a perk: commuting from South Bay to SF on Caltrain is a major hassle (that is assuming the offices of the company are located to close to Caltrain -- public transportation within SF proper is a nightmare unless you work and live close to BART station) and leaves no time to pick kids up from school/drop them off at school/curricular activities. I should add that at least Google and Facebook run buses within suburban South Bay as well -- so the worst part of the commute (going North on 101 in the morning, South on 101 in the evening) can be avoided. I should add there are also people living further in various bedroom communities in East Bay like Albany or Walnut Creek, or San Ramon (which also have good schools) and most of those folks either work for SF-based companies (keep in mind Google does have an SF office as well), or make use of company busses (Google runs busses to SF), or work from home some days a week. This would also be a huge generalization, but one can also think of the Bay Area as the OSI stack: application/presentation in SF, mid-tier (databases at Oracle, distributed infrastructure at Google and FB) in Peninsula/Northern parts of South Bay, and physical layer (Apple, Cisco, Juniper, Intel, etc...) in Sunnyvale and further south. So for companies that do more systems-level development, there's both network effects (they're hiring people coming from other companies in the area), and the need to somewhat more experienced engineers (who are more likely to have families and to own vs. rent). (background: lived in South Bay Area since I was 13, worked as an engineer in various South Bay Area software/Internet companies -- both in office parks as well as offices in more walkable downtown areas -- since late teens, including at Facebook in the Menlo Park campus).