Google is recruiting at a high rate and getting the best mathematicians, computer theorists and engineers on the planet.
One of the attractions they are offering is a free shuttle bus from three locations in San Francisco. Their office is nearly 40 miles away.
This can only be driving up the rents in San Francisco. A few years ago the bus was carrying hundreds a day. It must be close to a thousand by now. That is enough people to affect rental prices at the high end of the residential rental market.