A friend just pointed me to an interesting blog entry from CampaignMonitor. It makes the following conclusions based on analyzing the email client usage of more than 300 million people from January to June 2009:
It continues to blow us away just how quickly the iPhone is moving mobile email forward. The iPhone now caters for 5.78% of the email client market, breezing past Gmail to become the 5th most popular email client in the world.
Put another way, iPhone now has more of the email client market than AOL, Lotus Notes, Thunderbird and Entourage combined. That's pretty incredible considering it's a mobile device and a relative newcomer compared to the rest of the market.
Thanks to their software update approach within iTunes, iPhone users are also prolific updaters. iPhone OS 1.0 and 2.0 are amongst the fastest shrinking email clients, while iPhone OS 3.0 is by far the fastest growing email client version on the market.