Mailbox - email questions answeredOf the many email statistics that blow my mind, I think this one wows me the most:

Email reaches three times more people than Twitter and Facebook combined.

That’s a lot of people! (3.6 billion or so.)

Clearly email marketing deserves your time and attention. And like any aspect of marketing, there can be a learning curve to discover the ins and outs and best practices. Hopefully these answers to ten of the most common and important email questions can make the learning curve a little less steep.

1. How do I grow my email list?

Often, when I’m browsing the web, I’ll come across a blog with a stunning newsletter subscription form, boasting thousands of subscribers. I’m kinda jealous.

Email signup Convince and Convert

Big subscriber numbers are something we all want, so it’s good to know there are many smart ways of going about growing a list.

But first, let me start with one way NOT to grow: Purchasing email addresses.

Buying email addresses is frowned upon by most major email service providers (e.g., Mailchimp, which won’t let you even add a purchased list). More importantly for you, the quality of these leads is poor. These aren’t people who have shown interest in your product organically, so you’re already fighting an uphill battle.

Instead of buying subscribers, try earning them through quality content and asking permission. Here are some tactics for growing your list the right way.

Create an offer

Any piece of quality content will do. Build an e-book out of a series of blog posts. Put together an e-mail course. Then once you have your offer, ask folks for an email address in order to access the content.

Sites like Copyblogger have been highly successful at growing their list this way. Here is an example from the sidebar of the Copyblogger blog, teasing both free e-books and a free marketing course.

Create an Offer form - Copyblogger

Use subscription forms

You’ll never get an email address if you never ask for one. (Duh, I know, but stay with me.) The University of Alberta famously boosted subscribers 500 percent with a popup survey asking nothing more complicated than: “Would you like to sign up for our email?”

University of Alberta nudge Qualaroo

Popup surveys are one of many locations for a subscription form. Consider adding one to the sidebar of your blog, as a popup for those reading your articles, or in a call-to-action on your main page or in your footer. We use the first two locations for the signup form on the Buffer blog.

Make great partnerships

You are likely to find willing subscribers at other places around the Internet by partnering with sites that fit your focus. Featured in Vero’s email marketing guide, GrooveHQ has grown from small potatoes to over 7,000 subscribers by building strong relationships with others in their industry.

The key is to be helpful: Provide great content that your peers find valuable, and you’ve likely found yourself a partner. (Then be sure to close the deal by asking for email signups.)

2. What is the best day of the week / time of day to send an email?

I hate to burst your bubble, but there is no magic bullet for an optimal time to send email. The “right time” varies by so many factors and from list to list. Kissmetrics has a great way of putting it:

Your own email timing data is the best data you can get your hands on!

The best time to send your email will be unique to your list. That being said, there are some trends in open rates and clickthrough rates that provide a good starting point for some tests. Here is a snippet from a helpful infographic created by Kissmetrics.

Best time to send an email

Best email by time of day

(Click here for the full infographic.)

The takeaway: Weekends and mornings have the highest open rates and clickthroughs.

Data like this supports previous studies in favor of the morning/weekend send. One theory for the success is that there is less competition in the inbox at these times. With fewer other emails to distract, yours shines brightest.

3. How often should I send email to my subscribers?

I won’t cop out on this one either (but I probably should). Your own data will teach you a lot about optimal email frequency, but here’s a good rule of thumb to follow, courtesy of the Crazy Egg blog: Send email in a slowly regressing way.

Email frequency - how often should I send email?

A practical application of this could be with those who sign up to receive a free ebook from your site. Those signups can be added to an autoresponder series that sends a message once every day for the first week, then every other day, then slowly tapering off. Eventually, the only emails the subscriber receives would be an RSS email with blog updates or a newsletter.

Bottom line: People will open good emails no matter how often you send them.

Still, be aware that those who just met you might want to hear from you more often.

4. How does a spam filter work?

I was surprised to learn that spam filters go way beyond just the words and phrases in your email. It takes more than just a single mention of Viagra or Cash Now. Filters are quite a bit more advanced than that.

Here’s how content filtering actually works: A spam filter assigns points to an email based on the spammy elements found throughout the email. Each offense carries a point value, and if the total points exceed the spam threshhold – voila, you have yourself some spam.

What this means is that you cannot automatically end up in a spam filter for one misstep. It takes many.  And ultimately, your reputation for sending good email and your engagement record with subscribers will trump almost all.

To play it safe, though, you can review the full list of spam tests run by Spam Assassin. Keep in mind that the list is constantly changing as spammers learn and adapt. You’ll see plenty of spammy words and phrases here. You’ll also find some other interesting bits. Here are some that caught my attention:

  • An exclamation point and a question mark in a subject (.201 points)
  • Subject is all CAPS (.763 points)
  • Claims to honor unsubscribe request (2.063 points)

and by far the strangest …

  • Talks about Oprah with an exclamation (.666 points)

Included in the Spam Assassin list is a lengthy section on the words and phrases to avoid. Always Interactive has compiled a list of 100 of the worst offenders as well, if you’re anxious to know what puts filters on alert.

List of spam words - Spam Assassin

5. What metrics should I track?

There are two titans of email marketing statistics:

  • Open rate: The number of recipients who opened or viewed your email.
  • Click-through rate: Percentage of recipients who clicked at least one link in your email.

Certainly, you should follow up each campaign by checking these two numbers. Industry averages range, but in general, a 15 to 20 percent open rate is healthy and a 1 to 3 percent clickthrough rate is good.

Consider opens and clicks to be your bread and butter. You’ll still need fruits and vegetables (and desserts), right? Here are some other vital metrics that help complete the analytics picture for your email campaigns.

Click-to-open rate: Of the subscribers who opened the email, how many clicked?

Whereas click-through rate is based on total emails sent, click-to-open rate is based on total emails opened. This will help you measure the quality of your copy and design better than the overall clickthrough rate will.

You may have to calculate this yourself if your email provider doesn’t provide it. Simply take the number of unique clicks and divide by unique opens. Can you figure out the click-to-open rate of the below stats?

Opens and clicks

All those who got 32 percent give yourself a gold star!


It is possible that your email is merely a stop along your funnel, in which case you will want to follow up to see how the email converted. Conversion tracking requires that you dig deeper beyond the first open or click of an email and to track the user trail all the way to the end. You’ll likely need to get your website analytics involved in this step.

Email list health and deliverability

Having hundreds of thousands of subscribers is only a good thing if hundreds of thousands are engaged with your emails. When lists balloon in size and not quality, huge percentages of the list can result in bad email addresses or disinterest. This negatively impacts whether or not your message reaches the inbox (deliverability) as email services tend to frown on places that send bulk email with a lot of bad ends.

The good news is that proper list health – which could involve pruning a list dramatically or scrubbing out all the zombie subscribers – can lead to big results.

Here is an example shared by Jesse Littlewood on the Litmus blog about a non-profit agency that saw big results after slimming down.

Corporate Accountability took a radical step: they cut down on their email list by 40%. … In the months that followed, despite sending fewer emails, their open rates doubled, their click-through rates increased by 50%, and, most importantly, they raised more money from the year-end appeal. …With better insights they communicated better with their audience; with fewer emails they raised more money.

6. What is an A/B test?

You’ve heard of Always Be Closing. I’d like to propose a new maxim for email: Always Be Testing.

A/B tests are your way to find out more about the campaigns you send. They work the same way that an A/B test on a website might work: You show one group an A option and another group a B option and see which option gets the best results.

For email, this can lead to huge insights on the way you send your campaigns. Here are some top areas to target with an email A/B test:

  • Time of day / day of week
  • Subject
  • “From” name
  • Images vs. text
  • Preheader message

7. Where should I spend the most time on my email?

Certainly, there is a lot to consider for sending an email marketing campaign. It’s easy to get lost in a sea of options, so here’s an exercise to try: Put yourself in a subscriber’s shoes. (Should be easy; you probably get a ton of email yourself!)

What will make the subscriber open your email? What will he or she see first? Their eyes will go in a pattern something like this:

  1. Who sent the email (“from” name)
  2. What the email is about (subject)

These are the elements that will determine whether or not your subscriber even proceeds to the body of your email.

In other words, spend quality time coming up with a quality subject. Here are some options for a good workflow.

1. Write your subject line first

Before the design. Before the copy. Before the amazing call-to-action you know is going to rock the world of email marketing.

Write your subject line first, and tackle the rest second.

2. Schedule time in your workflow to write you subject line

OK, let’s say you’re incredibly set in your ways with designing and writing your HTML email first. You can keep it that way, as long as you make sure to schedule an appropriate amount of time for your subject. Yes, it is that important. If you have two hours to create your campaign, spend an hour-and-a-half on the design and copy and the remaining half hour on your all-important subject.

8. What is the ideal length for my subject line?

In general, keep the subject line shorter than 50 characters.

Specifically, MailerMailer found that the ideal subject line length is 28-39 characters.

What does that length look like in practice? Here are some examples of 28-39 character email subjects.

Canva name and subject

Digg name and subject

Litmus has a comprehensive infographic on what goes into the perfect subject line. Their tips include leveraging localization, asking questions, and keeping things brief. Here is a snippet. The full version is available at the Litmus blog.

Litmus infographic on subject lines


9. How do I make my email look good everywhere?

The latest numbers on email opens confirm that mobile is hugely important.

Forty-nine percent of emails are opened on a mobile device.

That means that half your audience will be viewing your email on a screen three inches wide and the other half could be viewing on a screen 14 inches wide. How do you bridge that gap in one well-designed message?

Answer: Responsive email design. Much like responsive web design, responsive emails look good no matter where they are viewed because they have specific styles for specific screen sizes. You can find beautiful responsive templates on Theme Forest, Campaign Monitor, and in most major email service providers.

Squarepath email template by Stamp Ready

If you’d prefer a quicker fix, try this: Design a one-column email. One-column emails scale beautifully because there are no sidebars to squish the content as the screen size decreases. One column emails are as simple as they come and work great on almost any screen.

Sqwiggle email

10. Are there any rules to email marketing?

Yes, and they aren’t just rules—they’re laws. In the United States, the CAN-SPAM Act legislates good and bad email with some specific guidelines. If you are sending commercial email, you must do the following.

  • Include an unsubscribe link
  • Include your brick-and-mortar address or your P.O. box
  • Honor someone’s unsubscribe request by never emailing them again
  • Avoid purchasing a list

Penalties for not following the law can be as severe as a $300 fine for each recipient of your email.

Your turn

Do you have a question that didn’t make the list? Ask away in the comments, and I’ll do my best to give you an answer!

P.S. If you like this post, you might also like 8 Effective Email Marketing Strategies, Backed by Science and 18 Tips and Tools for Managing Email Successfully.

Image credits: FlickrKiss Metrics, Crazy Egg, Litmus, ThemeForest

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Written by Kevan Lee

Director of marketing at Buffer, the social media publishing tool for brands, agencies, and marketers. We’ve got a new podcast! ?

  • This was like an awesome course on everything important about email marketing. I agree that the key point is to looks for ways to organically grow an email list.

    • Thanks, Murugan! Organic growth is super important. Have you found a way that works for you?

      • One important characteristic to display is authenticity; allows for others to learn more about who you really are and your brand.

        • Agreed. Good one!

  • Joey Kelly

    Or just don’t send out spam emails.

    • That’s a great start! 🙂

  • Norman

    I’ve never seen a metric that suggests open rates to be highest on Saturday. My own experience, the metrics provided by Mailchimp, Aweber and the vast majority of studies shows wed/thrs to be the highest days for opens and Saturday to be one of the worst. Not sure what Kissmetrics is thinking.

    • Kissmetrics’ numbers are courtesy of @danzarella and @pure360. Maybe that could explain the discrepancy with Mailchimp and Aweber?

  • Guest

    Your metric

  • Your metrics to track really depend on the goal of each send. For some sends it might be pretty similar, but a good approach is to first identify your goal for sending and then how you can measure that.

    Example: one send your goal might be to get feedback (in either replies or through a form), another send it might be leads for a products, or actual revenue from products sold, while for another send you might want just want to get as many of your readers actually visiting/reading the article you sent them.

    I have several columns in my custom “dashboard” to #1. identify my goal. #2. identify how I’ll measure it. #3. List the metrics that will give me a good indication on how well I did/didn’t accomplish that stated goal – usually as a conversion rate on the intended action (whether that’s a reply, a click, a purchase etc). I’ve found these to be much more actionable vs the Open/CTR stats are more of a “well, we didn’t completely drive off the road” 🙂

    • Wow, what valuable insight. Thanks, Olivia. I love to hear how email practices actually work in the wild, and your system makes complete sense! Do you use a service to track or your own handmade spreadsheet?

      • Thanks Kevan. I use a spreadsheet since it’s constantly evolving. But I do also have a “cheat sheet” checklist that I run through for all my newsletter sends to cut down on things I have to remember – which I also offer as a newsletter signup “freebie/offer” {so meta!}

  • Timely. I have a to-do item to send out an email this week to “my list.”

    Had no idea about needing to include my PO Box or physical address.

    • The physical address tripped me up for awhile, too. It was the last thing on my mind when sending an email. 🙂

  • Roxanne Brown

    Great article! Bookmarked 🙂

    For deliverability, IMO, paying close attention to acquisition practices and database hygiene/maintenance is the single most effective way to maintain your sender reputation. Over and over I’ve seen the kind of increases in delivery and click-through rates that Jesse Littlewood’s article described, simply by “clearing out the dead wood” using a confirmation or reengagement campaign.

    • So glad to hear this technique works for you, Roxanne. Seems counterintuitive, doesn’t it? The results speak for themselves.

      • Roxanne Brown

        I used to jokingly refer to those clients who wouldn’t hear of anything that would decrease their subscriber count as “size queens.” 😉 Like a great many things, bigger’s not always better!

  • Akash Agarwal

    It’s truly a nice post. All the questions on email marketing are very useful and answers are well to. Thanks for sharing.

  • Lone

    Awesome tips!!

  • Vera Rabkina

    The best article on e-mail marketing I’ve ever read. Thank you

  • jasperwillem

    Very important for me in newsletters is (and it goes wrong a lot), that if I am a (paying) member of a web-service and I get interest based newsletters from that service, I want them to consider my settings of that mediums.

    Aslo I would like links to end @ the articles advertised. I don’t want to end up on the Homepage / Landings-page and navigate to the link from the newsletter’s article.

    When the web-service of a newsletter is behind a log in, I don’t have problems to log in before reading the article, but I don’t want to end up on the homepage after log in, I want to read the article. Then another thing… if open 10 links from the newsletter, and I log in @ the first tab of my browser, I don’t want to log in in the next 9 tabs, I just like to refresh. Make sure your session manager accepts this behavior.

    Also, if you update an article header in your CMS, and you have done out a newsletter about that article, make sure it not dead-ends in a 404, but @ the page of the new endpoint.

    And as a side-node for your consideration, I don’t like to read newsletters that open with sponsored content, I just delete them.

    • All good tips (agree 100% about considering your settings). Thanks for sharing!

  • jessebarron

    Glad to see that I am already doing many of these things. I have a growing newsletter and have an e-course by email that I power with Drip ( I am still struggle with subject lines (headlines, too), but getting better with continued testing. I was never a fan of the click bait headlines, but that seems to be popular these days… so long as you end up delivering.

    • I’m interested to hear your take on Drip. I looked around a bit when it debuted and thought it seemed like a great product.

      • jessebarron

        I love it. It has all of the bells and whistles, while still keeping it simple and it is focused on its sole mission… which I’m sure you know a lot of companies have difficulty with. No feature bloat, just what you need to put effective drip marketing campaigns on autopilot.

  • Cori Hemmah

    Great article, but I disagree with #7. The most time should be spent on making sure the email displays correctly on every device your recipient might open it on (#9). You can spend all day creating great content and an awesome subject line, but if somebody opens the email and the images are enormous and the tables are misaligned, etc., they’re not going to engage with it and you basically just wasted your time. Litmus is an awesome tool for making sure your emails look good everywhere.

    • It’s an interesting discussion, isn’t it? I completely see your point about needing an email to have utility on whatever device is being used. I think that’s a great point!

      • John Lilly

        It is critical to make this happen as we have all abruptly exited an email for this reason.

  • Kevan, this is so freaking good. I was blown away by the mobile stat (49% email opened on a mobile device). Email marketers are lucky to have A/B testing readily available for their subject lines, but if people want to narrow down a list to find the best top two, I created a free tool to test titles/subject lines with a survey:

  • Jessica Swingle

    Great article, Kevan. It’s so easy to become overwhelmed by media…by far I pay closer attention to emails than other social media sources so the 49% makes sense. Thank you for sharing your thoughts and data on this subject. Helpful information.

  • Kate Larking

    Great summary for e-mail marketing. Thank you!

  • Bruce Nuffer

    Regarding spam, I’ve long had a single question. We have a sophisticated spam filter where I work, and it even flags my own test emails as spam. Yet there are a couple actual spam emails I get regularly that make it past the filters despite breaking nearly every example in the list above. They regularly include dollar signs and exclamation points in the subject line, include text that says ON SALE! and SHOP NOW, and have unsubscribe info (that doesn’t actually work). How do they get past the filters?? They aren’t embedding this info in images, this is actual text.

  • Great points with optimizing email marketing performance. Cannot agree more. Recently I wrote an article on how to benchmark email open rates –

  • Don’t write comments often, but just want to say how impressive this article was. Great Great info!

  • Great post! Always learning and doing… and more and more being a fan of this Buffer Team 😉

    • So awesome to hear, Rico! 🙂

  • Jeffrey Conover

    Interesting that CAN-SPAM dictates that email marketers should avoid purchasing a list. Andrew Mason has said that GROUPON had its first uptick upon buying a very good email list.

  • Grabiel Vega

    Great tips! For growing your lists, I would also advice encouraging your followers on social medias to subscribe to your newsletters, some services let you share your newsletters via Twitter and Facebook 🙂

  • Marcin
  • I once did a contest and offered my services free for their email. That did really well in collecting their email. So offering something valuable is def the way to go here. Good Post Kevan:)

    • Hi Luke! Thanks for the comment. Awesome idea to try out a contest. 🙂

  • Sid

    any advice with regards to catchy subject lines?

  • Chandana Raja

    Good post! There are various metrics that an email marketer must follow while sending an email to the subscribers. Few of them are hard bounce,soft bounce, click rate,open rate, spam percentage,churn rate,delivery rate,earnings per click ,inbox placement,forward rate,email reply rate. Each of these play a major role in increasing the ROI.They have been explained individually here!