Some marketers think that to avoid being delivered into the junk or spam folder, they have to avoid certain words that can cause alerts in spam filters. And that’s it.

Nothing is further from the truth nowadays.

Other factors, such as authentication, reputation and message construction are more critical if messages are to land in inboxes, writes Stefan Pollard in a new article at ClickZ.

Spam filters such as SpamAssassin, an open-source spam-filter program, has an extensive list of triggers that set off the filter. But, that’s not all. There are hundreds of tests on a message, that will assign a point value based on the likelihood of the elements to be used in spam messages.

Only after the message accumulates too many points that the system flags it as spam.

More issues are also likely to trigger filters and collect higher point values than those assigned to words in the message body. They include:

• Incorrectly formatted or incomplete e-mail headers, which list technical details of the message transfer, including the sender’s IP and e-mail sending address
• Broken tags and sloppy HTML coding
• Too large an image relative to the amount of text
• Scripting that could launch viruses or spyware
• Attachments
• URLs or domains that have appeared in spam

Although marketers have to select their words carefully, using the word “free” in the subject line is something they can do as long as they provide the right kind of offer in the message.

Nowadays, recipients have all the rights to click on the spam button to flag a message as such. If your message looks like spam and recipients can’t tell the message is from you, even the most careful choice of words can’t help.