Do you use email to deliver your content to readers? If so, then you should learn how to write irresistible email subject lines to motivate as many people as possible to open your message and read the content inside. Email is a great tool to expand your readership and increase your content's exposure to a broader audience, but it's useless if your subject lines don't make anyone feel compelled to open the messages and read the content inside.Ronn Levine of the Specialized Information Publishers Association (SIPA) shared results from a recent study on email subject lines conducted by U.K.-based email service provider Adestra through the SIPAlert Daily email newsletter that is delivered to SIPA members. You can download the Adestra report to read all of the details, but following is an overview of what works in email subject lines these days.

1. Shorter subject lines with highly focused and carefully selected words generate the highest engagement levels by intriguing readers to click through and read more.
2. Longer subject lines (over 90 characters) get the best open rates when they include a lot of benefits. For one offer, stick to fewer than 30 characters in your email subject line. Avoid subject lines between 30-60 characters which are considered the "dead zone."
3. Use a dollar sign or pound sign early in your subject line to boost performance.
4. The word "sale" drives the highest open rates, but other promotional words like "free," "discount," "half-price," and "save" don't perform well. Instead, write a subject line that communicates real, specific value.
5. The word "newsletter" does not perform well in email subject lines. Use words like "alert," "breaking," "news," or "update" instead. These words create a stronger sense of urgency and interest.
6. The word "report" does not perform as well as "research" in email subject lines. "Issue" and "latest" perform well, but "forecast" and "whitepaper" do not.
7. The words "ROI," "asset," and "industry" do not perform well. On the other hand, "profit" performs well, followed by "money" and "revenue."
8. Communicate exclusive and relevant content in subject lines that refer to events.
9. Personalized subject lines are good, but they're much better when the personalization is included within the email, too. This doesn't mean you should personalize the greeting only. You should also personalize the body content by referring to the recipient's most recent transaction or other personal detail.
10. Social networks drive poor response rates overall.

These are great points to keep in mind as you create future email subject lines to share and promote your Authoritative Content. Focus on communicating the value and usefulness of the content within your email, and your open rates and click-throughs should increase.Image: Simon Stratford