I foud my way to Does email really reduce IQ ? via Larvatus Proteo, where the New Scientist report on email gets damned as corporate spin.
I'm not sure the critique is persuasuaive. The Stroop effect has been known since 1935. Scientific American Mind carried a report on The limits of multitasking (subscription requird) that seems to agree with the infomania thesis. I'd write more, but some email came in.