Rok beat me to it
"Most marketers remain skeptical of using RSS as a mechanism to supplement their e-mail marketing newsletter content," states the report. It also says this is becasue consumer adoption of RSS readers remains low
But further down in the article it says that thirty-five percent of the surveyed marketers have deployed — or soon will — RSS because of consumer demand.
This seems very contradictory to me.
Rok Hrastnik of Marketing Studies also pointed out that while there may be obstacles to RSS adoption, there are many more reasons to do so than replacing your email.