I was going to make the same comment and then I realized blurring it is pretty useless: that info is in the JS snippet for GA on that site (and yes the key is the same).
The technique from the dheera.com article won't work well in this case because the filter is applied non-uniformly as a targeted spot. It becomes much more difficult to generate pixelated patterns to compare against. The Gaussian blur does however enable the simpler use of deconvolution to reveal the obscured digits.
