There are several articles on the subject of sending, receiving and managing spam. Please refer to the one that fits your needs best:
Sending Spam: What you can and can't do.
Spam Prevention Tips: What you can do about it.
Standard Spam Filtering: What we do for all clients. (this article)
Premium Spam Filtering: At modest additional cost.
Spam is unsolicited (unwanted) email. In order to minimize the impact of spam on our clients, we provide a spam filtering and tagging system.
Spam Filtering & Tagging
Our spam tagging & removal system is designed to protect our clients from incoming spam. Our standard filtering system removes about half the mail that hits our mail servers. This level of spam filtering is good enough for many clients. However, we offer a premium service for those who really need it. The premium service is offered at a additional cost because system resources for highly effective spam removal are so significant. Our premium service removes or quarantines nearly all your spam based on settings you select. You decide whether to quarantine it for later review or delete it completely.
How It Works
Our system decides whether a message is spam based on a complex point system. It then places fields in your message headers that will help you identify and deal with spam. If a message is given over 8 points, the message is determined to be spam by our standard filtering system and is deleted. A header tag is added to all other messages called X-Spam-Level.
In this tag, the number of asterisks is equivalent to the integer number of points, in this example, there are 6. Rather than actually filter mail with less than 8 points as spam and unintentionally delete a message that you might want, we simply tag the message with information in the header that tells you how many points the message received. It is then up to you to either sign up for our premium filtering service or turn on filters in your mail client so you can avoid seeing messages with any level lower than 8 points.
Filtering Tagged Messages
In order to recognize tagged mail and avoid seeing messages that have been tagged, you must turn on a filter in your mail client. For example, you might include a filter that says, "If any header includes: '******', then delete the message." or you might move the message to a folder where you can look at it later and be sure it's not something you want to keep.
In addition to our filtering and tagging systems, there are other things you can do to reduce your load of incoming spam.