Deferred Shading and Ambient occlusion

Over the past four or so days, I have been rewriting the renderer of pdEngine to be deferred rather than forward. It is much easier than I thought to do this, even in Direct3D 9 (I will translate it to Direct3D 10 when I am satisfied).
With a deferred renderer, there are so many interesting things one can implement. One is ambient occlusion, and I had an idea for an improvement of this to use it for global illumination. Talking to people and searching I found someone already proposed a similar technique, described here. I have been following this to implement my Screen Space Directional Occlusion (SSDO). The attached image shows just the AO on the right, and the final image on the left. The framerates are bad on my old card, but don't judge it by that.