I think this is simply due to different generations of camera in use (see 'Cameras' section further down the article). The limited high res areas in the USA are mostly where previous low res imagery has been replaced, which is generally in bigger cities.  It's unclear whether there are plans to upgrade the whole country (or Australia, NZ, Japan which are also earlier generation cameras). One clear difference is that low res images can only be zoomed to 2 layers (which is a bit pointless), high res to 3.  : The paragraph re. June 10, 2008 is dubious - it is true that there were some earlier better images of SF but these were taken with a black van rather than a car, and presumably for whatever reason were later replaced with standard car camera generation 1 images. I don't think there's any evidence that face blurring ever actually lowered the resolution.  