How Anti-Spam Measures Impact on Your Email

Unsolicited commercial email, commonly referred to as spam, is now recognized as a major problem causing considerable costs (e.g., [Ferris Research 03]) and impacting on how people use email (e.g., [Fallows 03]). Anti-spam measures, such as email filters and server-based block lists, have become ubiquitous. There is a growing body of empirical and anecdotal evidence suggesting that apart from the desired effect of reducing the incoming spam load, anti-spam measures are also undermining the global email system in terms of reliability and usability [Lueg 04]. In this paper, we argue that one of the underlying problems is that current implementations of spam filters are not capable of assessing whether email was actually solicited or not as they merely test for the presence of certain features considered typical of spam messages.