My guess is that with all the whining CEOs in the Bay Area do about "how hard it is to find talent", this is the start of a long-term trend. Rents in the Bay Area have gone up about 10%/year for the last five years running (anecdote: my room cost 850/month five years ago, I moved out when it hit 1300/month) and with the new "Affordable housing" mandates (which the SF electorate voted for) coming into play, pretty much all construction is going to stop, because the economics of cross-subsidizing 1/3 of units (the new requirement) with the other two is pushing the unsubsidized units out of reach for all but the highest income-earners.

This place is mortgaging its future, and people are right to want out.

Source: http://www.sfhac.org/real-numbers-behind-prop-c/