Hi Inderific. We agree that the graphic is shocking and almost unbelievable. Zillow currently has 480 homes in Oakland listed as foreclosure sale or auction as of today (April 20, 2015). You can Google that info from any city by pulling up 'Zillow + Foreclosures + Name/City'
What the 'blue dots' can't show you is the full number homes that are bank owned by not on the market right now. Banks have been forced to release just a portion of foreclosure homes at a time in order to control the market some (the pricing, actually)
Here's the link to the Oakland sales:
BAD RAP Blog