Developing Email Marketing with Email Programs in Mind

Companies have learned email marketing can generate new business and retain current customers. Electronic newsletters and email advertisements also promote top-of-mind mentality and raise brand awareness.

When developing an email for marketing endeavors, it is important it looks and functions consistently on all computers, particularly when development includes HTML. This can be difficult when every computer is different, especially the email program each recipient is using. For example, a company can deliver a quarterly newsletter to several hundred of its clients. Some recipients will view this email using an email client such as Microsoft Outlook or Apple Mail while other recipients will view the same email in a web-based email program such as Google Mail or Yahoo! Mail.

The good news is all email programs are built to read emails consistently. However, like browsers, each email program will interpret certain items differently which can affect how they appear and function. These items may be discovered during email development and testing. Ideally, an email should appear and function best in the most common email program. This leads to the question, what is the most used email program?

Top Email Programs
Data collected from 250,000,000 email recipients using Litmus Fingerprint analysis tool. This chart shows the top 10 email clients by market share. Compiled 24 February 2010 by Litmus.
Email Program
Market Share
Microsoft Office
– 2003 and earlier
– 2007
– 34%
– 9%
Hotmail 17%
Yahoo! Mail 13%
Gmail 5%
Apple Mail 4%
iPhone 4%
Thunderbird 2.4%
Windows Live Mail 2%
AOL Mail 1.2%
Lotus Notes 0.4%
Others 8%

A recent report from Litmus, an email reporting tool developer, summarizes email program usage from February of 2010 across a pool of 250 million recipients. The three most used email programs during this time are Microsoft Outlook at 43%, Hotmail at 17%, and Yahoo! Mail at 13%. Microsoft Outlook 2003 and previous versions represent the majority of Microsoft Outlook users with the rest using Outlook 2007. Other popular email programs include Google Mail, Apple Mail, and Mozilla Thunderbird.

Another report from Campaign Monitor outlines email program popularity in 2009 from a pool of over half a billion recipients. While this report is older its results are similar. In 2009, Microsoft Outlook was the most popular email program used at 37%, followed by Hotmail at 16% and Yahoo! Mail at 14%. Again, Microsoft Office 2007 was significantly less popular than Microsoft Outlook 2003 and previous versions. Other popular email programs in 2009 include Apple Mail, Google Mail, and AOL.

It is safe to say Microsoft Outlook continues to be the most popular email client. Keep this in mind when developing and testing marketing-relating emails. If an email looks and functions properly in Microsoft Outlook, the majority of recipients can have a flawless experience. Of course, we always recommend testing emails in multiple email programs and not just Microsoft Outlook.

As time goes by we may see changes in email program trends. For example, the release of Microsoft Outlook 2010 will most likely decrease popularity of Microsoft Outlook 2003 and earlier versions while it and Microsoft Outlook 2007 increase in usage. Web-based email programs such as Google Mail and Hotmail are becoming more accepted as their availability and user-friendly interfaces improve their popularity. Additionally, expect more mobile devices to capture email popularity. Both reports indicate growing usage from iPhone devices for email viewing.