Jim Salter, Ars Technica:
I pretty frequently get requests for help from someone who has been impersonated—or whose child has been impersonated—via email. Even when you know how to "view headers" or "view source" in your email client, the spew of diagnostic wharrgarbl can be pretty overwhelming if you don't know what you're looking at. Today, we're going to step through a real-world set of (anonymized) email headers and describe the process of figuring out what's what.