I like their approximate people reached metric. I've answered at lot of VBA questions which get a lot of views but not necessarily from developers who might have an account. I suspect they are mostly anonymous users and thus the answers get a lot of views but relatively few votes.
I've looked at the 'people reached' metric and wondered: does this mean that, objectively speaking, the greatest impact I'll have on the world will turn out to have been a few stackoverflow answers?
Out of curiosity I've done code searches on identifying substrings and found code from my stackoverflow answers all over the place, though of course the hits tend to be in that long tail of seldom used code out there. Pretty sure my most used code would be in deliberate open source contributions.
