In the early years of the internet, ISP's began to deal with the problem of spam by filtering email they feared was suspicious. This filtering emphasized the email's content, meaning the actual words in the email were scrutinized in making filtering decisions. For a trip down memory lane, here's a list of "spam" words that the dedicated copywriter was supposed to avoid.

These days, most blocking/filtering decisions are based on the domain and IP reputations of the sender as well as those of the domains associated with the content of the email (EG image paths, destination urls, redirect paths). That's why it is so important to have your sending infrastructure properly in place.

Perhaps the lone exception is Spam Assassin, a program used by many companies for spam control. It uses the words in the email along with other factors in determining the inbox worthiness of an email. The critical point is that who you are and how you send are much more important than what you send.

Occasionally at ArcaMax, an advertiser will want to try to beat the spam filters when they use the word "free" by substituting "f.r.e.e." or some variation thereof, the way it was done back in 2002. Our response? TWSD - that's what spammers do! If you look and act like a spammer, you'll be treated as one. (Credit to the Word to the Wise email deliverability blog.)

If your offer is "free", say it's "free"! Not "f.r.e.e." or "f*r*e*e", or any other permutation. In persuasion, we want to lower prospect resistance, not increase it. We don't think telling a prospect that your product is "F_R_E_E" is really going to help!

There's a great article here on the "Email Skinny" blog if you'd like to read more about this concept.