• A subject line should be as short and descriptive as possible. The subject line should be informative and true. If your from name and address are not branded, the subject line should also provide assurance that the email comes from a trusted source. A general rule of thumb is to keep subject lines between 30-50 characters.
• A strong offer can be put right in the subject line. Evaluate your content to understand the likelihood of your message hitting spam filters, particularly if a high percentage of your list is at corporate domains. Corporate domains rely more on phrases or words that have been “tainted” by the spamming community. The major web-based email clients focus on your reputation more than your content.
• The from name and address can be as important as the subject line. A strong offer can be put right in the subject line, but it is important to use punctuation and grammar carefully to ensure that you are not perceived to be a spammer by the receiving ISP.
• The ‘from’ name and subject line should work in tandem. The ‘from’ line should communicate who you are as the sender. Do your best to not change this entry frequently and make it recognizable so that recipients understand that the email was sent by a reliable source.
• If you are cross promoting a sister brand, use the subject line to introduce the sister brand and do not change the ‘from’ address of the originally subscribed-to brand. Any other ‘from’ address is likely to increase complaints. For more information on cross promoting sister brands, please see our recent post on promoting sister brands.

That said, spammers use various tactics to fool people into opening their emails. Spammers often use words that announce a big incentive or urgency. We suggest testing certain keywords or alternative words to optimize your subject lines.

• Some key words and phrases such as “act now,” “trial,” “quote,” and “guarantee” can be tested against “complimentary,” “estimate,” “be our guest,” and “giveaway.”
• While “Free” performs well in subject lines (see Experian CheetahMail’s Free Shipping Report) you might try using “our treat” or “on the house” to see what works best for your brand.
• Avoid excessive punctuation — exclamation points, multiple periods (…), dollar signs ($$), etc.
• In the past putting full words in ALL CAPS was considered equivalent to shouting. Using all caps is a practice used by spammers. Test the use of all caps and monitor any drops in open rates potentially due to filtering.
• Using ‘Re:’ at the beginning of a subject line falsely leads the recipient to think the email is a reply to a previous email. This is a misleading tactic. This tactic is not CAN-SPAM compliant and creates a poor customer experience. If the recipient feels duped into opening an email, you might see an increase in abuse rates or unsubscribe requests.

Just a few little words/phrases in your subject line can make or break the success of your email marketing campaign, not just by impacting open rates but affecting deliverability too. To learn what works best, test. Following these subject line best practices can save your client from losing both excellent reputation and good subscribers.

NFL shop.com did a great job with not only the creative, but the subject line, the time they sent the email, and the segmentation. As far as I can tell only those with a preference set as being a Viking fan received this email.

The subject line was: Your Minnesota Vikings Just Won – Order Now & Get Free Shipping Over $75

Inaccurate personalization
In the first example the subscriber’s name is replaced by an obvious piece of placeholder text – “Mr. Soandso.” (That’s email-speak for Mr. So-And-So, for those of you scoring at home.)

Missing dynamic content
Sometimes email marketers forget to test their dynamic content rendering, and as a result, end up with tell-tale blank spaces within their emails. Dynamic content is one area which needs to be tested thoroughly to ensure that campaigns render properly to the final recipient. Wish list and abandoned shopping cart content areas are two places where marketers should double-check before clicking the send button.

Misspelled, poorly punctuated subject lines
The last example concerns a subject line with missing punctuation and a typo. The subject line received was “Hurry Sale Starte Today – New Items Just Reduced!” First, the word “starte” should be starts. Secondly, what exactly is a “Hurry Sale?” How about a comma? The subject line should have been “Hurry, Sale Starts Today – New Items Just Reduced!”

Avoiding these mistakes is really quite simple – test dynamic content, test personalization, and proofread subject lines. If you can, get a second set of eyes to help you proofread and test everything before it goes out.

Do you have any examples of email mistakes? How do these errors reflect on the email sender? How do these mistakes make the recipient feel? Let us know your opinion!