Types of Spam
Spam has several definitions, varying by the source.
* Unsolicited bulk e-mail (UBE) unsolicited e-mail, sent in large quantities.
* Unsolicited commercial e-mail (UCE) this more restrictive definition is used by regulators whose mandate is to regulate commerce, such as the U.S. Federal Trade Commission.
* Any email message that is fraudulent.
* Any email message where the senders identity is forged, or messages sent though unprotected SMTP servers, unauthorized proxies, or botnets.
Information courtesy of Wikipedia: http://en.wikipedia.org/wiki/Unsolicited_commercial_e-mail