Real-World Email Client Usage: The Hard Data

What email clients do people use at home? At work? Can they get HTML? What about Lotus Notes? The numbers weren’t out there -- so Edward ran a survey. The results are in.

The single biggest unknown in the world of email marketing is what email clients your customers and subscribers use. It’s not that people don’t want to know — my ClickZ cohorts and I get this question all the time. If you were at our spring E-Mail Strategies conference, you heard one question from the audience session after session, to panelist after panelists: “How many of my users are on AOL? How many of my readers can accept HTML email? Do I have to worry about Lotus Notes?”

At that conference, I promised to throw the collective weight of ClickZ and its parent,, into getting some hard data so we can put our collective estimates behind us. Over the past month, we’ve gone to readers asking them to tell us a little bit about their email habits. We ran a quick seven-question survey across several of our Web sites and collected a total of 500 responses.

Before jumping into it, I should just mention’s audience tends to be more technical than most. Though our questions made an effort to solicit answers for both business and consumer users (after all, every business person becomes a consumer when she’s off the job), I suspect real, true-blood “consumers” are slightly underreported in our survey. My 90-year-old grandmother tends not to read an enormous amount on Flash development or network security. But before I get ahead of myself, here are the numbers:

Q. How many active (i.e., you check this account at least once per week) email accounts do you have?
Email Acounts Adjusted Percentage
4 or more 29.09
3 28.08
2 29.09
1 12.93
0 0.81
Total 100.00

I was surprised by the high number of email accounts here. Personally, I only have three. Maybe I’m behind the times? This statistic probably gives more credence to the belief that many people use dedicated email accounts when registering for products or services online with the specific intent of avoiding email they don’t want. Hopefully, your campaign isn’t ending up here.

The next two questions get what I’m really after: what email clients people use:

Q. Which of the following email clients/accounts do you primarily use for work-related email?
Email/Client Adjusted Percentage
AOL 7.0 4.92
AOL 6.0 0.61
AOL 5.0 0.61
AOL 4.0 or lower 0
Microsoft Outlook 39.14
Microsoft Outlook Express 25.20
Eudora 4.30
Netscape 5.33
Hotmail 25.82
Yahoo Mail 19.67
Lotus Notes 6.35
UNIX Command-Line Based 1.43
Juno 0.61
Other (write-in optional) 19.06
Q. Which of the following email clients/accounts do you primarily use for personal email?
Email/Client Adjusted Percentage
AOL 7.0 6.52
AOL 6.0 0.81
AOL 5.0 0.81
AOL 4.0 or lower .20
Microsoft Outlook 24.03
Microsoft Outlook Express 27.70
Eudora 3.67
Netscape 5.30
Hotmail 33.20
Yahoo Mail 27.29
Lotus Notes 0.41
UNIX Command-Line Based 1.22
Juno 0.81
Other (write-in optional) 16.29

I was surprised to see AOL under 10 percent for both business and home use. Again, I believe this reflects our audience. This number is probably significantly higher for many of you, probably around 30 percent. I was especially glad to see AOL 7.0 (which can accept HTML email) was the standard and that previous versions of AOL were statistically insignificant.

It’s no surprise Microsoft’s Outlook and Outlook Express dominate the business landscape. What is surprising is how well Hotmail and Lotus Notes do with business users — 26 percent and 6 percent, respectively, both higher than I had expected. Interestingly, Hotmail and Yahoo Mail combined beat Outlook and Outlook Express combined with home users.

When it comes to receiving HTML email, the issue is seemingly moving away from capability and toward preference:

Are you capable of receiving HTML as well as text email formats?
Response Adjusted Percentage
Yes, I can receive both HTML and text. 89.18
No, I can not receive HTML-formatted email. 2.65
Don’t know/not sure 8.16
Total 100.00
Q. Do you prefer receiving HTML or text email?
Response Adjusted Percentage
HTML 41.95
Text 31.52
No preference 26.53
Total 100.00

It also appears the vast majority of people out there are still signing up for email newsletters, even if they’re not always reading the fine print:

Q. Do you currently subscribe to any email newsletters?
Response Adjusted Percentage
Yes 72.01
No 24.75
Not sure 3.24
Total 100.00
Q. When you subscribe to email newsletters or email announcements, do you read the provider’s privacy policy regarding information collected?
Response Adjusted Percentage
Yes, always 28.09
Sometimes 42.42
Rarely 21.63
Never 7.86
Total 100.00

My single biggest takeaway from the survey is the demise of text email clients. There’s no doubt about it, just about everyone can receive HTML email. Whether people want to is (literally) another question. This confirms something I’ve suspected for some time. Just a few months ago, we were looking for a guinea pig with a text-only email client so we could test some multipart mime mailings. But we couldn’t find one! Even our UNIX administrators, who are typically shackled to the command prompt, can accept HTML email.

With all the fancy AOL/HTML/text segmenting features many advanced email publishing systems include right out of the box these days, one might assume getting the right format to the right person is crucial. The numbers don’t bear this out. If you’re sweating over compatibility issues, you might be safe going with very simple HTML, knowing you’ll be able to reach the vast majority of your audience.

Of course, if your system has these features, go ahead and use them. It’s probably not worth getting all bent out of shape over. For many of us, the number of bounces as a percentage of the total list will far exceed the number of people who can’t read HTML. Remember, this advice comes from someone who is 100 percent confirmed double opt-in, with clean lists and high delivery success rates.

When it comes to HTML versus text email, it’s time to shift the debate away from capability and over to preference.

Got a question? Have a proposal for my next audience survey? Think I’m full of it? Let me know — send me email!


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