Answer:It is often what you don’t say that may get you into the filter. These days many ISPs and most major online services use Bayesian analysis to determine if a message may be spam. This type of spam filter looks at every word in the message and checks the number of times each word was previously used in a reported spam. If the words in your message add up and cross a threshold defined by the filter, your message is considered spam. Words with a negative score (used in real spam) will hurt you and words with a positive score (rarely seen in spam) will help you. There lies the secret to getting past the filters: knowing how to string positive words into your message. This is something spammers try to do, badly, but for professionals it takes only minutes to accomplish.
Professional e-mail marketers have resources that show, on a daily basis, the good words to use in a message to keep it "light" so it floats by the filters. The "word weights" change almost daily, so having access to large Bayesian filter databases is a must. Once you know the words you can use, creating well-constructed "light" sentences is easy. But use them only if you are having filtering problems. The sentence can be cleverly sewn into your message so it fits into the subject matter. Example: "your mileage may vary" and "contact your mail administrator if you have trouble receiving this message" both are very positive. Even those can eventually turn negative if they are over-used. This is an ongoing battle that every marketer in this industry faces. Sadly, even the word "please" used to be positive but it has been used in so many spams that it is now neutral offering nothing positive to a message.
John Brogan is the CTO of Global IntelliSystems (www.GLIQ.com)an e-mail marketing and campaign management service provider.