I find these surveys in all their forms to be garbage, whatever the purported outcome is. They're almost always online (because it's no-name, no-budget survey companies), self-selecting surveys, and they seldom have any relationship to reality. Lazy bloggers use it to fluff up coverage.
Funny that the Fortune guy posted it given that I called him out for a prior one - http://blog.yafla.com/Lazy_Surveys_Enable_A_Lazy_Press/
I have demolished more surveys than I care to explain. I just have lost the desire to point out how naive people are for falling for this nonsense again, and again, and again.
But again -- let's revisit it in a couple of months, after those millions of Android users have switched.