Error on Google Maps (White Spot) - How can that happen? (g.co)

Looks like the aerial camera operator stuck his gum in the wrong place. Har har.

Or perhaps the home owner was sunbathing and asked Google to obfuscate for the good of mankind.

If looks like there was something very bright there, probably a sun reflection, and older digital sensors have a problem with that, it's called "blooming" and "streaking". Basically the charge in one "pixel" is so high, it leaks to the neighboring pixels.

Example:

http://www.aerith.net/misao/pixy/tutorial/blooming.html