I see Lyris claims that Gmail's spam filters cause 3 percent false positives and they used to cause 44 percent earlier this year. What rubbish. And how sad that a major IT news outlet regurgitated them so uncritically.
There's no way that a real Gmail user is seeing that kind of FP percentage, no matter how they legitimately measure it (and there are several ways used, depending on whether you'd prefer to publish a tiny number or a big, scary number).
My estimate of Gmail's FP performance is about 0.01 to 0.02 percent. That's based on roughly one per week, and measured as a proportion of total email hitting the spam filter.Reading between the lines of Lyris's report, they're only measuring as proportion of inbound marketing email, which might explain why the headline figures are so high.
Frankly, these crazy numbers cast doubt on the rest of the statistics presented in this report. Lyris clearly has an agenda here -- to instill FUD in the minds of direct marketers so that they'll sign up to Lyris's services. That's nice...
Sadly, ZD were taken in by these shenanigans and presented the figures as an "IT Fact"