Cities in California are artificial concepts that mainly exist because the people there decided they didn't want to share property taxes with the poorer people next door. EPA is the worst example, but also see Piedmont which is literally inside Oakland, and then see every single SoCal city that outsiders think are parts of Los Angeles.
It's literally across the 101
The Facebook / Sun campus is there because it was cheap land
technically just over the border to the north in menlo.