Avoiding the Spam Filters and Other Email Marketing Tips

By Eddie Machaalani

Introduction
Email marketing, as many of us know, can be a powerful, inexpensive method of reaching our most active potential or existing customers. It can boost not only our direct sales, but also our credibility and referrals.

One of the major benefits of email marketing is that email is free, but obviously this is the same reason why spam has become so popular and so frustrating. With spam comes spam filters and with spam filters comes the blocking of legitimate email.

In this article I'll try and describe the basic steps that can help reduce the number of emails you send out that get blocked by spam filters -- hopefully resulting in a more rewarding marketing effort.

The right selection of words
Many spam filters work by analyzing the email based on its content and the words used. Many words -- such as free, sex and so forth -- are very heavy spam trigger keywords. Your priority should be to avoid such words while keeping your newsletter as professional as possible.

Later in this article I will show you a technique that I use to help me detect words that could trigger spam filters that I may have missed.

Email content and design

• Don't include too many images in your email (1-2 per email should suffice) or some filters will flag it
• Don't use images or send attachments that are too large. 300Kb should be the absolute max size of the email so be sure to make sure the total for images and attachments comes in well under that (adding a file to an email will increase the size by about 30% just in encoding it) so you need to take that into consideration too
• Don't include a single large image in your email if you can avoid it since this is how most spam nowadays seems to operate

Pay attention to your formatting
When formatting your email, keep it simple and professional. Excessive use of different colors, fonts, sizes, images and so forth will result in a higher spam filtering rate. Keep your email as clean as possible, and try to stick to a maximum of 2 or 3 different font types and sizes. Overly large sized fonts will surely add to an email being flagged as spam, as will too many images (or not enough text).

Try and use a short and simple stylesheet rather than using font tags excessively. Most spam filters don't appreciate a multitude of font tags and inline formatting, and the more primitive filters can't detect stylesheets so they will not penalize as easily.

Consistency is king
Use a template if you plan on sending newsletters consistently. This will make sure that all your newsletters look and feel the same. It will also add a touch of professionalism and branding to your newsletters.

Whilst not directly affecting spam filters, this will enable your readers to distinguish your newsletter instantly, thus not reporting it as spam accidentally. Some spam filters work by querying a spam server, whereas others report individual emails as spam. If your email gets reported as spam, then more than likely multiple spam filters will flag your email.

Being consistent with your timing of the newsletter also helps. For example, if you send a newsletter once per month (I personally don't recommend you send out any more than this, unless you've got something really interesting to say), then aim to send it out at the same time, on the same day each month.

Once again, your potential readers will learn to expect your email, adding professionalism and often improving open rates, also reducing accidental spam flagging as well.

Keep your lists as clean as possible

Honor all unsubscribe requests (your email marketing software should generate an unsubscribe link for all emails you send) and process bounced emails frequently. Sending to email addresses that have bounced repeatedly can result in a blacklisted IP address. You want to make sure that each bulk email you send does go out to legitimate, working email addresses.

You should also make sure your abuse@ and postmaster@ emails are valid and working. The Internet Engineering Task Force (IETF) has recommended these email addresses for complaint spam reporting and you may receive emails from users or ISP’s if they have a complaint or spam report about your mailings. 

Unsubscribe and Contact Information
Every newsletter you send out should contain a way for the reader to unsubscribe. Not doing so is illegal in some countries and is an instant sign of spamming. You should also display your contact information (Phone, Fax and Address) clearly, as this greatly increases confidence in your email and your company, as well as conforms to spam laws in the United States. Contact information also allows a potential customer to contact you if need be.

Test, Test, Test
The key to avoiding spam filters is testing. The first method of testing I use is to send the newsletter to multiple email accounts with existing spam filters. For example, I have a Gmail (http://www.gmail.com) account and a Hotmail (http://www.hotmail.com) account that I make sure I send my newsletter to. If the newsletter ends up in the junk folder, then I've got some work to do.

I also have a couple of email accounts with different web hosts that have spam filters in place. In particular, they mostly use spam assassin -- a popular piece of spam filtering software. Spam assassin is useful because every email that it flags as spam is given a report and a list of why that email was considered spam.

I also use a powerful spam filtering tool, which detects any spam related "triggers" based on Spam Assassin's scoring system. The scoring system is constantly updated so you will always stay on top of the latest spam filter changes. By using the spam assassin checking system -- gives me feedback as to why my email may have been flagged. If I’ve used words or formatting that I shouldn’t have, or if I’ve included too many images, etc.

More Ways to Avoid the Spam Filters

• Watch your attachments
  Many people don’t realize that the type of attachment you send with your email can cause different spam filters to block your email and even go so far as reporting your I.P to a black list database.
  
  You should avoid using script or any type of attachment besides PDF. Many corporate mailboxes as well as virus filters block attachments that end in .exe, .avi, .swf, .zip, etc.
  
   
• Use double opt-in lists
  I’ve mentioned this in my previous article but once again to make your mailing list as clean as possible always use double opt-in strategies. That is, when someone signs up they should receive an email which contains a link they must click to verify that they do indeed want to be on your mailing list. This stops illegitimate email addresses from being added to your mailing list.

Conclusion
Although there's no fail-safe way to absolutely guarantee all of the emails you send will reach the intended recipients, simply by applying the techniques described in this article can dramatically help to improve your email deliverability and hopefully your click thru rate and bottom line.

In conclusion, I hope that you've found the above tips useful and I wish you luck with your email marketing endeavors!