Pivotal Veracity (PV) released a report on MarketingSherpa looking at how false positives impact email deliverability. PV opted into 100 company emails using a MSN-Hotmail, Yahoo, and Gmail account. During their six week study they received false positives from 54% of the companies. This number far exceeds previously reported number of 20% from Deliverability Service Providers (DSP).
Here is a link to a recent JupiterResearch report that ranks several top tier DSPs.
eINFO – a collection of articles and studies about email marketing.