Getting a contact's email address is only half the battle. The other half is keeping them as an engaged member of your subscriber list.

Your emails are only effective if they're read, and one of the most important factors that determine whether an email gets opened  or ignored is the subject line.

While there are a number of tactics and techniques you can use to generate an email subject line, I decided to do an audit of my own inbox and take a closer look at some of the recent email subject lines that actually captured my attention.

Why was I compelled to open them? What techniques were they employing to keep me engaged with their emails? Were there any evident trends that seemed to be effective?

Here's what I found.

Mind the curiosity gap

A curiosity gap is the space between what you know and what you need to know. It's an especially powerful writing technique for headlines and email subject lines because it drives the reader to keep hanging on to connect the dots and fill the gap with new knowledge. 

Let's see a few examples.

Subject Line: Amazing list of awesome — one more time! [MarketingProfs]

Why it worked: “List of awesome” could mean many things. While not quite the Upworthy level of curiosity gap (We Made a List of Awesome and You Won’t Believe What Happened Next), I still wanted in on the list of awesome simply because it sounded so great. It ended up being a list of events and speakers that were lined up for MarketingProfs’ 2015 B2B Marketing Forum, and the way the headline was written, I could feel the enthusiasm seeping throughout the entire email - what a way to generate buzz!

Subject Line: We’re painting the map orange! [Content Marketing Institute]

Why it worked: What could this possibly mean? Considering that the email came from Content Marketing Institute, and based on what’s insinuated by “painting the map”, anyone could probably figure out that this was going to be a CMI road show of some sort. Knowing I could solve this mystery once and for all with a simple click of my mouse, I did exactly that (mission accomplished, CMI).

Subject Line: Homer wasn’t a Greek poet… [Mixergy]

Why it worked: Yes, of course Homer was a Greek poet - I took a few courses in comparative literature in university, so I would know, Mixergy! This ended up being the lead-in to a great personal story from Andrew Warner of Mixergy, but the email subject line starts the story with a contradiction and a cliffhanger — if Homer wasn’t a Greek poet, what was he?! I had to know. Or maybe I’m just a nerd.

Pop culture appeal

Pop culture references don't always have a place in B2B marketing, but it's for that very reason that they can be incredibly effective.  When used properly, pop culture allusions can add a timely and human touch to your subject lines.

Here are a few that landed in my inbox.

Subject Line: Better dinner guest than Beyoncé? [Qzzr]

Why it worked: Being in a space that is full of utilitarian solutions, it’s not easy to make “sexy” B2B content, which is why Beyoncé stood out in my inbox like, well, like Queen B. Pop culture references present an interesting paradox in content marketing because they can be effective for the same reason they can be limiting or isolating: Either people get it, or they don’t. It’s important to truly know your audience and target your segments so you can effectively use pop culture references to show your human side and encourage engagement.

Subject Line: Missing Shark Week? Try Stack Week! [Lattice Engines]

Why it worked: As you can probably guess, this email arrived in my inbox shortly after the Discovery Channel’s annual Shark Week had ended. The appeal of this subject line was its timeliness, and as any marketer knows, timing is everything. Although it’s certainly not a new marketing tactic to ride topical trends, this was a refreshing twist on an otherwise run-of-the-mill B2B webinar invitation.

Subject Line: Hey! Here’s an amazing GIF [IFTTT]

Why it worked: IFTTT gets it — GIFs are an irresistible part of popular culture. And whether you like it or not, GIFs play a significant role in how we communicate today. Although it’s probably not an effective tactic to blast your email lists with GIFs and GIFs only, it is important to consider experimenting with new formats - Dell Computers tried it and saw a 103% increase in conversions from all emails sent that included GIFs.

Your human is showing

I know that a large majority of emails that land in my inbox are automated. And impersonal, sales-y copy doesn't help to conceal the fact that I'm nothing but a contact on a list to some organizations. When a brand allows their human side to show, it's far more enticing to engage with their email.

Subject Line: I’m getting married and I need your help… [Influitive]

Why it worked: Creating a human connection is transitioning from trend to best practice. Brands are slowly starting to peel away the layers to become more transparent and spark real human connections. And what better way to spark a human connection than to ask for marriage advice? This email from Influitive reminded me that I was more than a contact on a list and more than a customer — I was a human and I’m part of their brand story.

Subject Line: Ever Had This Problem? Tell me about it [Canva]

Why it worked: This is Dale Carnegie 101. Who doesn’t like to talk about their problems and believe that someone is actively listening on the other end? This email from Canva made me feel important, and as automated as it was, Canva did a great job of showing some empathy (a difficult feat for any bot to accomplish).

Nuggets  of expertise

If your emails aren't providing value, then there's no way your subscribers are going to care. One of the best ways to provide value is to help people do their jobs better.

Subject Line: 9 things only expert group managers know about LinkedIn Groups [LinkedIn]

Why it worked: 3 out of 4 people are motivated to learn online because they want to do their jobs better and, as my open on this email indicates, I fall into that majority. Offering exclusive, easily consumable expertise that is targeted to what I do is exactly the kind of thing I want to see in my inbox.

Subject Line: Finally, a webinar on account-based selling! [Datanyze]

Why it worked: This grandiose play — at last, the webinar you’ve all been waiting for! — cheekily highlights the value of the material presented here. B2B marketers get a TON of webinar invitations, and Datanyze did a great job of making theirs stand out by showing that they know what their audience wants, and they're the best source to give it to them.

Subject Line: Pop Quiz: Can you fix this sentence? [Grammarly]

Why it worked: Challenge accepted, Grammarly. The power of quizzes is undeniable - Qzzr put it best: “‘Stop telling me interesting and useful things about myself’ - said no one ever”. Whether it’s to learn an outcome or test your knowledge, quizzes are one of the only forms of content out there that are “all about me”, which is why they’re so effective at presenting nuggets of information.

Subject Line: 2-Minute Blogging Trick [Kim Roach]

Why it worked: Kim Roach knows that nobody’s got more than 2 minutes to spare when trying to achieve Inbox Zero. A 2-minute trick is exactly what a nugget of expertise should be. Bite-sized content is still incredibly effective, especially when consumed from one’s inbox. Give it a try!

Conclusion

Of course, I'm obliged to run a couple of disclaimers, the first being that the inbox is a subjective place — just because I opened an email with Beyoncé in the subject line doesn't mean everyone else will.  This means that it's more important than ever to segment your lists and keep your messaging as hyper-targeted as it can possibly be.

Finally, not all of these subject line techniques will necessarily work for your brand, but they might be worth testing — you never know what's going to work until you try! Happy emailing.