Spoofing is the creation of TCP/IP packets using somebody else's IP address. Routers use the "destination IP" address in order to forward packets through the Internet, but ignore the "source IP" address. That address is only used by the destination machine when it responds back to the source.

A common misconception is that "IP spoofing" can be used to hide your IP address while surfing the Internet, chatting on-line, sending e-mail, and so forth. This is generally not true. Forging the source IP address causes the responses to be misdirected, meaning you cannot create a normal network connection.

However, IP spoofing is an integral part of many network attacks that do not need to see responses (blind spoofing).

"Phishing" scams -- those phony e-mail messages demanding that recipients verify their financial data by clicking a link to log into a fake version of their bank or credit card issuer's site.

A whitelist is a list of e-mail addresses or domain names from which an e-mail blocking program will allow messages to be received.

DHA’s (directory harvest attacks) are brute force attempts by spammers to find valid e-mail addresses where the spammer connects to business’s e-mail server and guesses addresses until he gets some right. Those addresses are then harvested for use in later spam campaigns.

Pay-Per-Performance is using a company such a NexTag, DealTimeNetwork, or ShopWithTheWeb.com to market your merchandise, where your company will only have to pay for the click if it results in a sale

Abuse/Complaint Rate is the number of AOL complaints/AOL message delivered. An important metric to look at to gauge satisfaction.

Unique links are how many different links are in an e-mail message. So if you have lots of links (URLs) you could look at which specific content is driving the clicks/interest. An example would be travel e-mails... how many clicks are coming from airline offers, hotel offers, car offers, loyalty program offers, etc.