It always appears like that because he's written it so that when the "Google" cells are active, they appear darker than normal active cells. Whether these cells get activated or not follow the normal rules of Conway's game of live. So yeah, it's organic, but with a little trickery, the "Google" stands out as the pixels in the area blink on and off.

You can confirm this by pausing the simulation and clicking on all the cells in the region to switch them to the 'active' state: http://imageshack.us/a/img138/2751/71405409.png