That's interesting, but it makes sense -- SF is a city of primarily renters. In more suburban/residential areas, rents went up because people lose their houses and needed somewhere to live. Supply went down, because there was more demand for rental stock but the foreclosed houses largely sat vacant for months or years.

(I actually did 'negotiate' a rent decrease in ~2008 in Santa Clara; they wanted $150/mo MORE, so I pointed to a unit on their website that was $120/mo LESS, and said I wanted to rent that one instead. Needless to say, they made me an offer to stay put, thank god.. having to move across a parking lot would have been miserable. But of course rents in general took off despite this small blip)