Whether email is increasingly being consumed on mobile devices is no longer a question: it’s a fact. But does that mean the days of the desktop are over?

Not so fast.

Data from nearly 6 million email marketing campaigns suggests the shift to mobile has made it more difficult to get readers to engage with your content… unless you can drive a subsequent open in a different environment.

This report will help marketers understand how readers interact with email campaigns on mobile devices vs. the desktop. It includes benchmarks on open rates across different clients, advice on improving rendering, data on the relationship between opens and clicks by environment, and an overview of behaviors that increase the likelihood of a reader engaging with your content.

If a mobile reader opens an email again from a different device, more clicks happen.

Chapter 1

Open rate benchmarks

Data for over 1.8 billion opens from campaigns sent in 2013 shows that mobile is the most popular environment for a subscriber’s first interaction with an email.

Opens by environment in 2013

  • 1%
  • 1%
  • 1%

The shift towards mobile has also been rapid. From 2011 to 2013, email opens on mobile phones devices increased by 30%. Mobile first took the lead in the fourth quarter of 2012.

Opens by Mobile Device

Nevertheless, the overall trend towards opening email on mobile devices is undeniable. The iPhone is the most common mobile device that subscribers use to open their email for the first time. Between iPad, iPhone and iPod Touch, nearly 90% of all mobile opens happened on an Apple device. Marketers should note that this data is likely skewed by the fact that Apple devices will display images by default – thereby automatically registering an open – whereas many Android email clients don’t.

The rapid shift towards – and overall popularity of – mobile means playing it safe with a basic one-column layout isn’t enough anymore. Marketers need to focus on creating the most compelling content possible, so responsive design is no longer a luxury — it’s a necessity. Check out our Guide to Responsive Design for helpful hints on ensuring your emails render beautifully across all mobile devices.

  • iPhone – 61%
  • Android – 12%
  • iPad – 26%
  • iPod Touch – 1%

Opens by Desktop Client

Opens on desktop clients account for more than a quarter of all opens, and the desktop landscape is quite fragmented. Across all editions, Outlook accounts for 56% of all desktop opens and nearly 16% of total opens in any environment. Unfortunately, the fact that the majority of desktop opens happen in different editions of Outlook doesn’t make life any easier for email marketers. Each edition of Outlook has its own unique rendering challenges, making it notoriously difficult to code for. In fact, the newer versions of Outlook for Windows are more difficult to work with than older ones: 2000 and 2003 render HTML email using Internet Explorer, whereas 2007, 2010 and 2013 render the HTML using Microsoft Word.

The release of the new desktop client Outlook 2013 will drive a decline in opens on Outlook 2000, 2003 and Express, so Word-based rendering isn’t going away anytime soon. The good news is that Outlook 2013 renders very similarly to Outlook 2007 and Outlook 2010 so if you’ve already optimized for these environments, no big adjustments to your email templates are needed to support the new client. For the inevitable bugs that do come up, check out our Guide to CSS in Email.

  • Outlook 2010 – 22%
  • Outlook 00/03/XP – 19%
  • Outlook 2007 – 15%
  • Apple Mail 6 – 14%
  • Windows Live – 10%
  • Apple Mail 4 – 9%
  • Apple Mail 5 – 8%
  • Apple Mail 3 – 2%
  • Thunderbird – 1%
  • Outlook 2013 – 1%

Opens by Webmail Client

Hotmail was rebranded as Outlook.com in 2013 and together they account for nearly half of all opens that happen from webmail clients.

The rebranding introduced a new set of display challenges for email marketers and coders: most notably, Outlook.com removed support for the margin property – a CSS fundamental. They also have styling on paragraph and list tags that’s tricky to override. Bottom line — if you’re not careful, you may see your beautiful campaign render in a less than optimal way for 1 out of 10 of your readers on average. Our Guide to CSS in Email can help email designers navigate the complexities of coding for Outlook and other desktop clients.

  • Outlook.com – 48%
  • Yahoo – 25%
  • Gmail – 25%
  • AOL Mail – 2%
Chapter 2

The impact of mobile on click-through rate

At the same time opens have been shifting towards mobile devices, we’ve seen a correlating decrease in click-through rates – with a 10% decline in 2013 vs. 2012. Aggregate opens rates, on the other hand, have stayed more steady in recent years.

Open Rates vs. Click through rates: 2011 – 2013

Clearly, there’s been a shift in email consumption that is more prominently reflected in aggregate CTRs than opens. While there are several factors that may be contributing here – including an increase in the sheer volume of email sent — it’s also worth trying to isolate the impact of the shift to opening email on mobile devices has had.

First off, keep in mind that the most common time to click on an email is when it’s initially opened.

87% of clicks will happen when a reader opens an email for the first time.

So accordingly, since initial opens are increasingly happening on mobile devices it is more common for a click to happen on a mobile device than it is on a web or desktop client. In fact, one out of every three clicks occurs on a mobile device today.

Distribution of clicks by environment: Q1'13 - Q1'14

  • 1%
  • 1%
  • 1%

However, when you isolate opens on mobile devices, less clicks are happening on the initial open than when you look across all environments.

Only 78% of clicks on mobile devices happen on the first open.

And when you go on to compare clicks as a percentage of opens, it’s immediately clear that an open on a mobile device doesn’t hold the same relationship to a click that it does elsewhere.

Percentage of clicks relative to opens by environment

  • 1%
  • 1%
  • 1%

Additionally, the percentage of clicks relative to opens on mobile is decreasing, even as it stays fairly steady in webmail and desktop clients. Though mobile devices are growing in popularity for first time opens, the trend suggests it’s becoming more difficult to turn those opens into clicks.

Chapter 3

Triage: Fact or Fiction?

From looking at the ratio of clicks to opens alone, we can see that users consume email differently on mobile devices. But are they in fact “triaging” – or flagging emails to read later on different devices? To answer that, let’s first take a look at the end-to-end behavior of people who first open their emails on mobile devices.

How mobile readers interact with email


Open campaigns on a mobile device


Click a link after opening


Open the campaign for a second time


Do nothing


Open on the same device


Click on the same device


Open on a different device


Click on a different device

Nearly one-quarter of people who open on a mobile device will open an email again. But it’s still more common for that second open to be on a mobile device than it is on a different device: 70% will stick with their mobile device, and 30% will go elsewhere. So does screen size really factor into the way readers consume content? The data certainly suggests so.

Mobile readers who open emails a second time from their computer are 65% more likely to click through.

Does that make triage a reality? For a portion of readers, yes. But more importantly, the data suggests that it’s an email consumption habit that’s impossible to ignore because it signifies a greater level of engagement with the content of your message. The new standard in successful email marketing is not only capturing a subscriber’s attention – but holding it long enough to get them to return and engage with your content.

Chapter 4

Key takeaways

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