Gmail came in at only 5.5%.
They are tracking these based on loaded images, which means Gmail users by default aren't counted. Some versions of Outlook (at least 2000) autoload images. Lots of mobile devices don't load images, which makes BlackBerry users undercounted.
Not to mention sample bias--I also don't sign up for email newsletters.
tl;dr those stats are a hot steaming pile
Outlook 2000 is 4 (maybe 5) versions old. At least 2010, 2007 and 2003 don't load images by default, I wouldn't be surprised if Outlook XP didn't either.
More to the point: no large organization is using Outlook 2000 anymore. It's unsupported and you can get 2010, 2007, 2003 or even XP on your current license agreement.
And many people have more than one email address and in a corporate environment, it shouldn't be surprising Gmail falls below 10%.
- what percentage of GMail users regularly schedule more than one event a week?
- what percentage of Gmail users use reminders?
- How much of their day is spent with GMail open?
- How often do they search Google contacts for phone numbers and other data?
If you include Outlook Express, then you have to consider that it had the same tying advantages that IE had over other browsers. Even so, it's been months since I ran across someone who uses Outlook or Outlook Express for personal email. Thunderbird and Apple Mail are somewhat more common among the people I deal with, but the majority of people I deal with use some kind of web mail for their personal email, with GMail completely dominating among those who are at least slightly technical and among kids.
Outlook is pretty much the de facto mail client amongst my clients, even those that aren't in business environments. My largest business client is email-program-agnostic, and still the vast majority of users are asking for Outlook.
Among webmail users, most usage is either Comcast's site, Yahoo's (a result of the SBC partnership), or their internet service provider's.
Actually, I think this might help put it in perspective: more of my clients have email addresses at their own domain versus having Gmail accounts.
A user could, if he so chose, have email addresses at their own domain, on Gmail, AND use Outlook to access it. There's a VERY blurry line between the usage patterns of the average mail user.
That said, I agree with you in thinking the parent was underestimating Outlook's prevalence.
"Our goal is to do what Gmail did to Outlook: replace a popular desktop application with a better online version."
is badly begging the question. I'd be surprised if gmail + Google calendar had more active users than Outlook.