The most popular e-mail client

During the past week a colleague sent me a link to Campaign Monitor’s statistics on e-mail client popularity. A first glance shows Outlook to be the most popular, Lotus Notes to be absolutely nowhere, and iOS devices to be the strong-performing new kids on the block.

However, it’s very important to look at the way that the statistics have been collected. Campaign Monitor use a request to a remote image in their e-mail, and then can check the type of client that makes the request. Now, this would be accurate if not for three things:

  1. Many e-mail clients don’t show remote images by default (it’s a good mechanism for not indicating live e-mail accounts to spammers). Notes 8.x, most versions of Outlook, and Mozilla Thunderbird will block remote images. Typically I won’t load the images if I’m not interested in the content, and I suspect many other people exhibit that behaviour. So many of Campaign Monitor’s e-mails will go unregistered, thus skewing their statistics.
  2. The statistics mash together personal and business e-mail accounts. Hotmail, Yahoo! mail, GMail (although Google may argue), Apple Mail, Outlook Express and Thunderbird are predominantly personal e-mail solutions. Full Outlook and Notes are predominantly used in business environments. The mobile platforms (iOS, Android) are likely to figure in both sets. All I’m saying is that it would be more illustrative to take a view of the personal and enterprise markets separately. In business Outlook and Notes would outstrip the others, therefore it’s unfair to show Notes with such a small share. For personal accounts the picture would be completely different.
  3. Spam filters – are Campaign Monitor’s e-mails getting stopped by spam filters before they get to business users? Maybe, and again that will skew the Outlook and Notes statistics, and probably for the business-used mobile platforms too.

The survey then lists the ‘movers and shakers’ compared to two years ago. The fact that iOS devices have grown most (84.23%) is no surprise, although actually I would have expected more. The fact that Notes has fallen (by roughly the same amount) is also no surprise, knowing what’s been happening in the enterprise market over the past few years. However, I refer to point #1 above – older versions of Notes (and I mean 7 and older) didn’t have the ability to block remote images. Notes 8.x does have that ability. So the same population of Notes users, but with more using Notes 8.x, would show less usage using Campaign Monitor’s method of gathering statistics.


  1. I don’t fully understand your arguments. Everything you wrote that somehow skews the result is equally valid for both Outlook and Notes. That does not explain the 27.62% score of Outlook and (probably) <1% share of Notes. Even if they lumped the Outlook and Outlook express combined into one slot, I highly doubt that Outlook itself would score badly.

  2. What I was saying was that the Notes score is unfairly low because the take-up of Notes 8.x has been quite high among Notes customers, and because Notes 8.x supports blocking of remote images many of the clients in use may not be registering in the results. The same is probably true of Outlook too. And because companies have good spam management, some of Campaign Monitor’s e-mails may not get through to Notes or Outlook users.

    My overall point was that their method of working out e-mail popularity is flawed. Also, note that “Unable to detect email client” accounts for 10% of the results. If they were doing a bad job of identifying one particular mail client, then that’s an awful lot to add to one of the products.

  3. Sure it’s unfair against Notes, but this isn’t the point. Nobody claimed that this was a statistic that shows the truth about email client usage. It’s just campaing monitors finding. The interesting part is, that Outlook 2010 isn’t adopted fast enough, to offset the decline of the older MS clients and that people can live with easier (but faster) clients, like Apple Mail. The bells and whistles of Outlook don’t sell and most users don’t care about the client. Which is good and bad.
    It does not say anything about the servers either.

  4. Christian, I agree that this isn’t an accurate study of the e-mail market (as I said, it’s flawed), it’s purely a snapshot based on the stats they could gather through one method. However, I disagree on two of your points:

    1) That there should be any comparison between the use of Apple Mail and full Outlook. I don’t believe that Apple Mail is used as an enterprise e-mail client, whereas Outlook is. It’s likely that people who use Apple Mail do so for personal accounts and will probably use Outlook at work.

    2) That their stats provide any evidence about the take-up of Outlook 2010 – as they’re measuring by requests made to remote images, Outlook 2010 won’t send many requests. But Outlook 2010 shows nearly twice as much usage as Notes, which is a widely-deployed (albeit shrinking) client.

  5. I’m surprised people are doing surveys like this still – the point of delivery is somewhat fluid – for example the company I work for has Exchange – so Outlook at work and on the VPN, Firefox for the home access via a browser. The most recent change is that a lot of my emails are now “You have been sent a message by . Click to read this message” type of emails, taking me away from the email client into a separate web place (like Facebook) where I then communicate. The “market share” question should really be the traffic changes between Email (Outlook/Hotmail/Notes/Gmail) and other forms (Facebook/Twitter/LinkedIn/SMS) – Communication (even work) is becoming more social and frivolous, and less desk-bound 9 to 5. Like this blog in fact!

  6. @Darren. Why shouldn’t apple Mail be used as an enterprise mail client?
    It does, all you need. In Switzerland Apple has almost 20% market share. Today, higher management has a MacBook to show off, not a ThinkPad anymore. Do you really think, they all use Entourage?
    I think it is a mistake, to use the low number stats in any regard. Everything below 5 percent is not accurate anyway. That is also a flaw, if you want, the pseudo accuracy. But they just published their results, without any claim to be accurate for the whole world.
    As I found out this year, there isn’t a good statistic about email client/server usage. This one is as good as others, or as bad as others. Outlook fans will like it, because it proves for them that Outlook still the King. Others rather see the difference between 2009 and 2011, were Outlook lost a lot. For Notes fans, its hard, for Notes haters its THE proof. But the only thing which has some degree of accuracy, is an overall trend to mobile and from my point of view, a trend to easier mail clients. But about my findings, we could argue for days and imagine hundreds of reasons why I am right or wrong. It just does not lead to any better conclusion, because nobody can prove it, without an in dept and independent study, which hasen’t been done, or probably hasen’t been published.
    PS: In the mean time, you can read in my blog, what I thought about it.

  7. Interesting about 20% market share for Mac in Switzerland – certainly higher than the UK. But tell me this, if you use Apple Mail plus iCal with Exchange do you get the full range of calendar & scheduling features that business users would require? That’s an honest question, I don’t know the answer. I suspect some functionality but not everything (free-time search for example). So I’m wondering if someone with a Mac uses Apple Mail configured for Exchange, or maybe uses Entourage (or even Outlook 2011, which I have)… or uses Outlook Web Access.

    Overall I’m not disagreeing with you – this isn’t an accurate study. And you’re right that the most obvious trend is the rise of mobile devices, and I’m sure that will continue.

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