From Mind Hacks, which turns up such gems (and thoughtful essays) with astonishing regularity
Last September's Journal of Forensic Sciences had an intriguing study comparing email and handwritten threats to members of the United States Congress.
While threats by letter were more thoughtfully composed, they need to taken more seriously as they were more often followed by a threatening physical approach and more frequently written by people with a significant criminal history.A comparison of email versus letter threat contacts toward members of the United States Congress.
J Forensic Sci. 2007 Sep;52(5):1142-7
Schoeneman-Morris KA, Scalora MJ, Chang GH, Zimmerman WJ, Garner Y.
To better understand inappropriate correspondence sent to public officials, 301 letter cases and 99 email cases were randomly selected from the United States Capitol Police investigative case files and compared. Results indicate that letter writers were significantly more likely than emailers to exhibit indicators of serious mental illness (SMI), engage in target dispersion, use multiple methods of contact, and make a problematic approach toward their target. Emailers were significantly more likely than letter writers to focus on government concerns, use obscene language, and display disorganization in their writing. Also, letter writers tended to be significantly older, have more criminal history, and write longer communications. A multivariate model found that disorganization, SMI symptoms, problematic physical approach, and target dispersion significantly differentiated between the correspondence groups. The group differences illuminated by this study reveal that letter writers are engaging in behavior that is higher risk for problematic approach than are emailers.