This statement is taken for the rule by many email marketers. Despite of a magic power of this word that prompts the recipient to immediately act on your email, it’s generally believed that "free" is a pure spam word. Yes, there is a truth behind this. Every other spam message contains the word "free". But what is the most important is the environment this word is used in, i.e. the whole phrase with the word "free" matters.
Let’s look how two popular spam content filters – Spam Assassin and MS Outlook 2000 – work and handle your emails.
Spam Assassin, one of the main “test” spam filters, assigns points – positive and negative – to the message content and HTML code. Positive points mean potential spam, negative points mean the message content and code are not generally used by spammers. The score is calculated and if it exceeds a certain level, the message is filtered as spam. It’s about the Spam Assassin user to determine the level at which emails are filtered. It is generally believed that most companies/ISPs use a total score of around 10, but that some may go as low as 4.
In the Spam Assassin the phrases with the word "free" do get fairly high scores – 1 and higher. But the phrases commonly used in legitimate emails such as “free report”, "free download", "free upgrade", “free e-book” and “free newsletter” are not affected.
Unlike the Spam Assassin, MS Outlook 2000 Junk E-mail Filter uses a pass/fail method. It looks for “junk and adult” content in the message and directs suspicious messages to the Outlook’s Deleted Items folder. The common things that trigger the filter are the use of an exclamation point and the word "free" in the message Subject line.
The bottom line: Use the word "free" in your email newsletters wisely and test, test and test your message before sending it to the whole list.