For many years Microsoft Outlook was the most popular email client in the world. According to the latest research, Microsoft Exchange Server accounts for more than half of business mailboxes in 2014; that is, 500m in absolute figures. Many of these users are using Microsoft Outlook, where Outlook Web Access still plays a companion role.
The installation base of Microsoft Office is about 1 billion. This figure can be found in many articles. In 2014 Microsoft reported that over 1.1 billion people use Microsoft Office. So the estimated base of Microsoft Outlook users in 2014 is between 500m and 600m.
According to the Google Trends, in the USA we can see decreasing interest in Microsoft Outlook in the last 10 years:
Does that mean that the market share of Microsoft Outlook is decreasing? We think that it does not. Outlook is not a new product, many people have used it over the years and familiar with it. So, we can interpret this reduced interest as a decreased need for information about the product, but not a reduction in the market share.
In recent years mobile devices have flourished. About 500m IPhones and over 1 billion Android smartphones are sold to this moment. According the different surveys and researches, 75-80% of iPhone users check email by smartphone. The number of phones in use is less than a number of sold phones. We can estimate that 25% of iPhones sold have been broken or replaced by a newer model. Polling indicates that the average iPhone is damaged or destroyed within 10 weeks after purchase.
So, what is the estimated number of iPhone email users? It is between 250m and 350m. This is two times less than Microsoft Outlook email users and Outlook has the chance to maintain its domination in 2014-2015. We also must take into account that the iPhone is now a companion, not direct competitor for Outlook. Many people check email on their iPhone and send replies from Outlook. This is especially true of business users and corporate mail.
Unfortunately, there is no reliable research on email client popularity in recent last years. But we point your attention to very popular statistics from Litmus. This company specializes in commercial mailing for a large number of clients, tracking email sent and collecting statistics. Below are June statistics from Litmus with the annual trend:
These statistics are based on 552 million opened emails. To track an email opening, the company inserts a link to a small picture to the email body, which is downloaded when the user opens the email. The company warns that this method has serious flaws, and that data may be over- or under-represented due to image blocking.
From our point of view, this data is amusing, but nothing more. We can see that Gmail sailed from 3% to 14% in six months. In November of 2013, Gmail started to show inline pictures automatically in email and the Gmail share in the data its share increased 5 times. By default, the iPhone automatically loads images and Android does not. But why has Android fallen to a third of its rating in only half a year?
What can be said regarding Outlook from this data? By default, Outlook do not show inline images and downloading of images may be restricted in corporate networks. So most emails opened in Outlook are unlikely to be tracked, whereas all iPhone openings are tracked. The decrease in Outlook share in Litmus data is not accurate. It is like the situation with Gmail share a half-year ago.
Despite the fact that Litmus statistics show 25% of iPhone email openings and only 13% for Outlook, the real data, we think, are opposite. Microsoft Outlook still the most popular email client in the world. And will remain the most popular email client in 2014 and 2015.