What emails clients are being used out there?

This is not "exactly" a programming question, but it's highly related. We are writing an app that sends out email invitations for a client (no, it's not spam). Their designer gave us an HTML and CSS template to use which is fine. The problem is that it looks like crap in Outlook 2007 because Microsoft decided to use Word (of all things!) as the rendering engine for HTML in Outlook 2007. I want the client to understand that they should design a "compatible" look and would love to be able to show some kind of statistics about what email clients are being used out there, namely that Outlook 2007 is growing in use.

Has anyone run across any white papers, web sites, studies that even come close to providing a view on this? I don't expect census level accuracy, but something fairly credible would be good. Thanks for any help.

From stackoverflow John Virgolino

• you should look at ReturnPath - they somewhat specialize in that.

  Clients you likely need to consider (aside from Outlook): AOL GMail Yahoo Mail Hotmail Lotus Notes thunderbird

  From Rob Fuller

• If you expect to hit many business customers, remember that a very large potion of them will be using MS Office and Exchange Server and therefore also Outlook. If you're more aiming for home users most of them will either be using some webmail or a mail client that uses a regular HTML engine, like Windows Mail, Thunderbird, Opera Mail, Mac OS X Mail.app.

  From jfs

• I'm using gmail

  From Avner

• My understanding of the generally perceived best-practise on this, is is to code for the lowest-common denominator. There are plenty of email clients with enough use in-the-wild that aren't great at rendering "modern" HTML.

  Firstly, aim to send your mails as a 2-part multipart mime message. An HTML part AND a plain-text part.

  Secondly, try to avoid using CSS or positioned divs where possible. Use table-based layouts and inlined-styles. Preferably specifying as much of the style in HTML where possible.

  Try to keep images as inline IMG tags, or as table/row/cell background attributes only.

  The email world just isn't anywhere near as up-to-date, and more importantly, far more diverse than the browser world. If you follow these simple rules, your life is going to be much easier than taking a more advanced approach and repeatedly tweaking it in order to get your content to render satisfactorally on enough of the common clients.

  From Cheekysoft

• I use KMail, you should also look at Thunderbird, Outlook, Evolution, Lotus and Opera Mail.

  Also keep in mind many people use webmail such as GMail, Hotmail, Yahoo Mail etc. And some web mail (and mail-clients) work only in plain-text for security reasons.

  Personally I think that plain text emails are best, many people prefer not to allow HTML mails due to security reason and thus would just be viewing a badly formatted plain text mail anyway, regardless of what you send, so in my opinion it would be better to just use plain text.

  From HappySmileMan

• Gmail - personal mail

  Lotus Notes - forced to use it for corporate mail :(

  Lotus Notes sucks at rendering any HTML message correctly (we're running 6.5), and has only partial support for CSS. The best HTML messages for it are simple table-based layouts.

  From X-Cubed

• Raw market share figures will not help you much. When designing HTML email, the only thing that matters is what client your particular target population uses. This depends on geographical area, industry, B2B/B2C -- variations are huge in practice. In some industries (journalism...) you'll even have to reckon with a sizeable population using clients like Lotus Notes, which is notorious for supporting HTML barely more than nominally (shudder).

  Outlook 2007 can certainly not be neglected any more, in particular if you send to business addresses, but with Vista on new PCs it's also got a noticeable presence for private accounts.

  Return Path indeed have data according to industry.

  However, in practice, a good approach is to follow "save" guidelines, in a lowest common denominator style. Outlook 2007 is not the only problematic client -- Gmail is also quite notorious for lacking support for a number of design elements others display just fine. You'll find that a surprising number of web designers do run a sideline with HTML email design (there is demand and it helps pay the rent). If you just start out, Campaign Monitor (an email marketing provider) has a wealth of good resources. You could start with their 2008 Email Design Guidelines. They're also one of those behind the Email Standards Project.

  Oh, personally I use Thunderbird with IMAP, Gmail, and RoundCube.

  (Disclaimer/full disclosure: I actually work for a competitor, in the loose sense, of Campaing Monitor.)

  John Virgolino : The links are helpful, thanks!
  From chryss

• At work we have 3 x KMail and 4 x mac OSX' mail.
  Further webmail as fail-over (squirrelmail on mail server) in Firefox, Camino, Safari. We put the words in the mail, the rest in attachments.

  Words (pure text messages) can simply be copy/pasted, forwarded etc without formatting problems.

  Separate attachments lets user choose to view, download, save etc.

  This is the most universal way to use mail.

  From $pageUsers[$post.author].name

• I faced this issue some time back.. most of the clients (including web) block HTML! We just created a web version of the email and added this to the footer of the email "If you are not able to view the message click here (link to web version). It was simply because some people think that its not safe to display images ;-) so a better way to make them open and read beautiful html emails

  From Shoban

• I have outlook and gmail, but also a blackberry Curve...

  The curve is HORRIBLE at dealing with anything other than plain/text emails. Please have a link near the top to view the email on a website, and consider sending a multipart email that also has a text only section for clients that don't support HTML and such.

  From Scott S.

• I run M2 (Opera's built-in mail client) and always have it set to "prefer plain text" for mail bodies. I also have "Block external elements" turned on.

  From Shadow2531

• In absence of general statistics, collect your own.

  Check out http://fingerprintapp.com/email-client-stats for a ready-made statistics collection tool, and see http://www.mattbrindley.com/fingerprint-email-client-usage-1/ for a write-up about it. Matt Brindley also offers this gem: "So far only Outlook has proved as popular as we expected, the iPhone was a notable surprise for our own list, with Lotus Notes making an unexpected appearance as well."

  Of course, provide both text/html and text/plain mime types so that readers can choose which version to view, and keep your html extremely basic until your statistics indicate that you can get fancier.

  If Fingerprint's fee is out of the question, you can collect your own statistics. Include hyperlinks in your HTML. When your CGI application receives requests from these hyperlinks, it can save the HTTP_USER_AGENT in a database for your statistical analysis. This method is not entirely reliable because some readers will stick to plain text, some will never click any of the hyperlinks, and some email clients will not include useful information in the user agent request header, but it may give you enough information to proceed.

  Sitepoint, a well-respected source for W3 information, has an article, http://www.sitepoint.com/article/code-html-email-newsletters/, in which Tom Slavin points out:

  1. Use HTML tables to control the design layout and some presentation. You may be used to using pure CSS layouts for your web pages, but that approach just won't hold up in an email environment.

  2. Use inline CSS to control other presentation elements within your email, such as background colors and fonts.

  Slavin also recommends templates from Campaign Monitor and MailChimp to get you started.

  From Robin like the bird

• Also, I think if you send as both text/plain and text/html, Gmail users (of the webmail UI) have no choice but to view the text/html version.

  From Shadow2531

• I ran across this report / data that clearly shows Outlook 2007 gaining in popularity and heading in an upward curve. Currently this site reports the following top 4 clients (percentage out of 100% of course) but also that Outlook 2007 is on the rise. Hope this helps.

  http://www.campaignmonitor.com/stats/email-clients/#most_popular

  27.77% Outlook 2000, 2003, Express / 16.23% Hotmail / 14.14% Yahoo! Mail / 8.94% Outlook 2007

  From mxb