These days, many people take it for grantedthat their email is secure. People (and companies) send all kinds ofcritical information through email, expecting it to make it to thecorrect person and only that person.
That's a bad assumption.
Email is often used by Web applications to reset passwords, byfinancial sites to provide updates to profiles, and by friends andfamily with personal information. Any of this data, in the wrong hands,could be dangerous to a person. It could lead to all the usualproblems: identity theft, information exposure, and the exposure oftrade secrets.
Email passes through several servers in much the same way astraditional mail travels through several people. The sender sends anemail directly to an SMTP (or similar) server, which is often run bythe sender's Internet service provider (ISP). That server typicallyforwards the email to the recipient's mail server (which can be run bythe recipient's ISP, the recipient's company, or...