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40 Email Subject Lines Research Shows Your Subscribers Can't Resist

40 Email Subject Lines Research Shows Your Subscribers Can't Resist
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Your email list is potentially the most important asset your business owns. Search engine traffic and social media play a huge role in online marketing, but if I had to choose just one channel? It would absolutely be email.

Having access to your target market's inboxes gives you the opportunity to continuously send valuable content, and to build long-term relationships.

The trouble, of course, is you don't have a hope of building these relationships if your subscribers aren't opening your emails. According to Silverpop's 2014 Email Marketing Metrics Benchmark Study, the mean open rate across all countries is a mere 20.2 percent; this means that for every 100 emails that get sent, only 20 get opened.

While it's important not to get hung up comparing your open rates to those of other companies, monitoring your own open rates can point out areas for potential improvement. The Silverpop report says it best: "The open rate works best as an in-house benchmark to track over time, because it can signal progress or problems with engagement. It’s relatively unreliable because it doesn’t capture all opens accurately due to image blocking and other factors. In other words, track your open rate, but don’t use it as a sole measure of campaign success."

Related: 4 Revolutionary Behavioral Email Marketing Ideas

So, what does this all have to do with subject lines? Optimizing your email subject line is the #1 way to increase your open rates. For this reason, this post will look at all the latest research on subject lines, including which ones have performed best, and which keywords have resulted in the highest open rates. Just keep in mind that what works in one industry or niche may not work as well in another. Be sure to test these out for yourself!

So without further ado, here are 40 email subject lines and keywords to test with your own subscribers!

According to MailChimp's analysis of over 40 million emails, the 10 most effective (60-87% open rate) subject lines were:

1. [Business Name] Sales and Marketing Newsletter

2. Eye on the [Business Name] Update (Oct 31 - Nov 4)

3. [Business Name] Staff Shirts and Photos

4. [Business Name] May 2005 News Bulletin!

5. [Business Name] Newsletter - February 2006

6. [Business Name] Newsletter - January 2006 [ *|FNAME|* *|LNAME|* ]

7. [Business Name] and [Business Name] Invites You!

8. Happy Holidays from [Business Name]

9. ATTENTION [Business Name] Staff!

10. ATTENTION [Business Name] West Staff!!

Element to test in your own emails: Every single one of the top 10 subject lines above included the name of the business, and four of them also included a date or year. While using "newsletter" or "news bulletin" may no longer be as effective, using your business name in your subject lines may have a positive impact on your open rates.

Related: Email Subject Lines Can Really Suck. Here's How to Make Yours Better.

Digital Marketer analyzed the 125 million emails they sent in 2014 to determine which ones performed best. Here were their top 10 subject lines:

11. How (and why) to calculate Average Customer Value

12. [URGENT] You’ve got ONE DAY to watch this…

13. Check out my new “man cave” [PICS]

14. 212 blog post ideas

15.  A Native Ad in 60 Minutes or Less

16. Is this the hottest career in marketing?

17. Your 7-figure plan goes bye-bye at midnight…

18. Steal these email templates…

19. The Facebook Slap is coming…

20. [WEEKEND ONLY] Get this NOW before it’s gone…

Elements to test in your own emails: Try conveying a sense of urgency in your subject lines ("is coming", "get this now", "you have one day left", etc.). Using numbers is always a great way to grab attention as well ("7-figure plan", "212 ideas", "60 minutes or less"). Finally, test out using ellipse' (3 dots) at the end of your subject lines; five of the 10 subject lines above used this strategy.

Related: How to Write Better Email Subject Lines

Alchemy Worx analyzed 21 billion emails sent by 2,500 brands to find the top performing keywords used in email subject lines. The top five most effective words were:

21. Upgrade

22. Just

23. Content

24. Go

25. Wonderful

Elements to test in your own emails: Why not try including one of these five keywords in your subject line? Other keywords they found effective in various industries included several, sleeps and important.

In an analysis of over 2.2 billion emails, Adestra looked at which keywords were most effective across a variety of industries. Following were the top eight keywords according to their research.

26. Free delivery

27. Available

28. New

29. Alert

30. News

31. Update

32. Summer

32. Weekend

Elements to test in your own emails: According to the report, while content marketing is the 'it' topic this year, content marketing keywords performed poorly due to over-saturation in the market. They recommend referencing sales or discounts where possible, as well as using percentage off amounts (e.g. "40% off today").

Related: 6 Tried-and-True Email Marketing Tactics

In an older, yet still useful, analysis, Alchemy Worx looked at 24.6 billion emails sent. Here were the most effective keywords in terms of open rates:

33. Jokes

34. Promotional

35. Congratulations

36. Revision

37. Forecast

38. Snapshot

39. Token

40. Voluntary

Elements to test in your own emails: Try using the word "jokes" in your subject line, so long as it's relevant to the topic of your email. It produced the most significant results, netting a 117 percent higher than average open rate. Words to avoid, according to this research: videos, romantic and discussion all resulted in just over 30 percent less than average open rates.

Final thoughts.

I trust this post has given you some ideas to test out for your own subject lines. When in doubt, focus on using subject lines that accurately convey the content of your email; research has shown that simple and to-the-point almost always outperforms elaborate or clever.

And above all, keep in mind that what works for one business or audience may not work for the next. I've sent out thousands of emails in my life and different things work for different companies. When I owned Organize.com my subject lines were very different then with my current startup Due. Be sure to test out a variety of subject lines and keywords to see which ones work best for you.

Related: 3 Scary Email Marketing Mistakes to Avoid