The Ars summary of the report seems strange (I've not read the whole pdf) in a couple ways:
They talk about percentages of private behavior getting scooped, but not about percentages or numbers of credit card or bank account users/passwords (which they indicate were the primary targets of the botnets).
And weirdly, Ars says, "Torpig controllers may have exploited these credentials for between $83,000 and $8.3 million during that time period..." Funny numbers. ?it just happens that the range is 8.3 x 104 to 8.3 x 106 ? Makes me wonder about overall accuracy of post/report.