As many as 15% of your customers and prospects may never get your messages because they are incorrectly identified as spam. Even if your email address file is double opt-in, there are no guarantees of delivery. Current volumes of email messages have reached crisis levels forcing ISPs and corporate IT departments to deploy robust technologies to detect and quarantine unsolicited email. Unfortunately, some permission-based email messages are caught in the net and never reach their intended audience. Just last week, my mother sent a message that got caught in a spam filter that I use to monitor activity.

Applied Info Group has conducted messaging campaigns since 1996 and has amassed reliable predictors of email delivery success rates using programs that evaluate various spam filters. Spam filters are typically highly-generalized, inaccurate programs. Sophisticated spammers can avoid these filters while ethical marketers following the DMA guidelines are having legitimate messages snared. Marketers now need to adjust messages to maximize the chances of successful delivery while still maintaining effective communications.

To ensure delivery, it helps to know that spam filters look for patterns and add or delete points for certain factors. Then, if the total score reaches a predetermined level, the message is flagged as spam. By looking at what adds points (bad) and subtracts points (good), you can learn how to construct email messages that are less likely to get filtered.

These strategies can help your messages clear spam filters.

Use Capitalization Sparingly
Capital letters are seen as "yelling" and spammy and excessive use costs you points. Avoid using capitalized titles or headlines.

Watch Your Punctuation
When emailing, less is more when it comes to punctuation. Excessive use of punctuation marks such as '!!!' or '$$$' or even unusual punctuation like '*' or '^'draws unnecessary attention to your email message.

Change your HTML Code
If your HTML message contains more than 50% HTML tags (has very specific formatting), you will be given some bad points. You should always try to keep the HTML simple. Avoid highly stylized formats, HTML tables with thick borders, Java script contained in the message, and an HTML form.

Check Your Hyperlinks
Try to avoid links without an http:// prefix or link to URLs using IP address numbers instead of a domain name. Try not to use mailto links.

Use Color Prudently
A font color tag that isn't formatted quite right or not in the palette of 217 web safe colors will be negatively identified as will hidden letters the same color as the background color. Background colors other than white are not recommended. Black is the safest. Blue, Red, and Gray are the best colors to use. Green, Cyan, Yellow, Magenta, or Unknown colors are considered the worst.

Reduce the Use of Large Fonts and Characters
Avoid fonts larger than +2 or size 3 (normal). Use HTML headers in the future rather than font tags to increase font size.

Review Subject Lines and Content
Here is where copywriters need to be creative and apply print direct mail concepts to email, but with different words. The most common problems are words and characters like Free, Hello, Guarantee, a number, a '$' sign, To: username at front of subject, '?','!', white space, words in all capitals, No Fee, No Obligation, Special Promotion, Call Now, Savings are all picked up. The best way to discover what works is testing in the same way direct marketers have always tested postal mail.

Watch Your Volume
Do not repeatedly mail the same records over and over again. This is not a good thing to do from a marketing perspective either. We have installed frequency counters to ensure that individuals do not receive an excessive amount of mail. Also, some filters regulate based on the volume of mail that is received from a domain.

Review the Wording of Unsubscribe Information
It seems ironic that legitimate opt-in emailers are penalized for having unsubscribe information, but since so many spammers have bogus opt-out systems, it is apparently a spam indicator. For example: phrases like list removal information, remove, click to remove, claims that you can be removed from the list, claims to listen to some removal request list, to be removed, reply via email, unsubscribe, headers that say X-List-Unsubscribe can be troublesome.

You need to include ways to unsubscribe, of course, but avoid the phrase "click here" and substitute something like "use this link to" You should not use mailto e-mail links with "remove," or anything else, in the subject. Make sure that you do not use words like "unsubscribe" or "remove" in the URL.

Clearly Identify a Newsletter
Fortunately, being a legitimate newsletter lowers your spam score and will help lower your score if you send a newsletter with a Subject that contains newsletter header (list), Subject contains newsletter header (news), Subject contains newsletter header (in review), Subject contains a frequency - probable newsletter, Subject contains a month name - probable newsletter, Subject contains a date.

Implement a Signature Line
You're helped if your email contains an email signature since so many spam messages don't. It can be either a short signature or a long signature. It is better to have either signature with empty lines surrounding it.

Set Up a Test Account
It is important to set up test accounts at some of the major ISPs (i.e. Yahoo, AOL, and Hotmail) so that you can measure the deliverability of your emails by seeing whether they are being filtered or not.

Do not include Spam Law Compliance
It's very unwise to claim that you observe all the spam laws. Only spammers say that. If you mention House Bill 4176 or H.R 3113, it will raise a flag.

Regulate the Message Size
Since so many spam messages are under 20K, it is beneficial to have a message that is between 20K and 40K. Over 40K does not hurt you, but it does not help either.

Remove Spam Addresses from Your List
Occasionally, people add email addresses to your list just to get you in trouble with the anti-spammers. Try scanning your database for an email address that starts with abuse@, postmaster@, or nospam@. Sometimes an email address will be inserted that subscribes you to an auto responder each time you send out a message. You might scan for the word "subscribe" among your email addresses (though this one won't affect you with the spam filters).

Ask Subscribers to Put Your Address in their Address Books
Some email client programs such as AOL 8.0 and Hotmail have recently changed their interface to allow users to sort their mail into preferred folders. As people subscribe, ask them specifically to place you in their address book (AOL), "safe list" (Hotmail), or "white list" (some spam filters). That way your e-mail will come directly into their inbox. Asking may be a little trouble, but it may make the difference between your recipients seeing or not seeing your e-mail.

As in every business, there are always a few individuals that exploit a situation, which makes it more difficult for legitimate marketers. It is up to us to be proactive, fully comply with industry guidelines, and support reasonable legislation that will remove the true spammers. It is also critical to educate the industry, our customers, legislators, and privacy advocates that it is OK to communicate to customers using this medium just like we do in other mediums like TV, radio, magazines, newspapers, and direct mail. As we learn to communicate in this evolving media, we will have to incorporate new creative strategies to get the email delivered and opened.