The researchers have often been surprised to see the e-mail addresses used by our students and colleagues. Many students and faculty choose their own user names and choose their providers. E-mail addresses may provide an insight into the background and employment situation of the user. This study quantifies the impact that e-mail address choices have on the perceived credibility of the person who uses that account. The authors make recommendations on how individuals and institutions can maintain their credibility simply by adopting e-mail policies.