My friend Michele over at Family-Centered Life blogged an interesting piece regarding this titled: "The hazards of the written word....especially online." Her links will take you to an ABC News Report, with author Justin Kruger and his "Egocentrism Over E-Mails." There is also a similar report at this link:
http://www.apa.org/monitor/feb06/egos.html which covers this topic:
"An inability to step outside of one's own head may be behind e-mail miscommunication, according to recent research."
I found these reports to be very insightful.