Lightning is an unusual Mozilla application

Since the start of February, the statistics capabilities of have been upgraded. It is now possible to see the number of active users on a daily basis, where before it was only shown on a monthly basis. This shows some interesting facts about Lightning.

What is pretty apparent from the stats is that Lightning’s usage is much higher during the week than on the weekend. This is a stark contrast to Mozilla’s main application Firefox, which is usually used by more people on the weekend than during the week.
[UPDATE: As I was informed, Firefox’s usage numbers are also much higher during the week than on the weekend. It seems that I mixed up Firefox’s market share numbers (which are normally higher on the weekend than during the week) with its total usage numbers.]

On Windows the usage numbers during the week are about twice as high as on the weekends, while on the other operating systems (Linux, MacOS X, Solaris, *BSD, OS/2) the usage numbers are just about 30% – 40% lower on the weekends.

This seems to indicate that we have a lot of business users out there using Lightning and that most of these business users use Windows as their platform of choice.

What we also see is that roughly 87.5% – 89.1% of our users are on the Windows platform, 7.6% – 8.6% use Linux and 3.1% – 3.8% are MacOS X users. Users of other operating systems range between 0.13% and 0.16%.

Those of you, that want to play more with our download numbers, can do this on the Lightning Statistics Dashboard, where you can find much more data to play with.

PS: Don’t ask me about the low numbers on five days in early February. These are clearly incorrect and probably a result of an bug, that was fixed later on.


  1. Thunderbird / Lightning will do even better among business users if Mozilla incorporates the MAPI protocol support being developed by OpenChange ( A lot of those business users are using Thunderbird despite having to live with Exchange Server–a real pain.

  2. The bigger week-end decline (compared to Firefox) is typical for Thunderbird, not only Lightning.

  3. A good percentage of the emails I get at work are meeting invitations and updates. Without Lightning I would have to use Outlook (or at least Outlook Web Access) to deal with those. Sunbird doesn’t help there, either, unless we can get it to talk to Thunderbird for the invites. Maybe a small TB plugin that forwards the calendar stuff to Sunbird would be sufficient. Windows is pretty much a given for the desktop, even though the product is on Linux.

  4. Business users can also have a look at SOGo –
    It integrates perfectly with Mozilla Thunderbird and Lightning. It not only shares most of the UI parts of those but also functionality and virtually all data.
    Have a look at the screenshots and videos from the SOGo website.

  5. The broken stats at the start of February are addressed in and will be fixed eventually.

  6. The graphs are labelled Downloads, but you really mean Active Daily Users right ? Firefox usage goes down on the weekend too, not up.

  7. Yes, not many people use a calendar for entertainment! Hopefully this sharpens the focus for Tbird and Lightning. It’s good stuff right now, but there are a lot of things that could be improved, like syncing with more mobile devices, taking info out of an email to create an appointment, and it would be nice to have some way to exchange info with a project management program like openproj. But that will be a while I think. Anyway, keep up the good work and good luck.

  8. As Wil mentioned, the missing stats at the beginning of Feb will be filled in (soon I hope!). Also, that abnormal spike on March 5/6 is going away today.
    Unfortunately, you were mis-informed about the weekend usage of Firefox being higher. It may have been true many years ago before Firefox was mainstream, but now-a-days, we see the same peaks and valleys for Firefox and Thunderbird.

  9. Thank you very much for mentioning the market share statistic. That is actually something interesting that our market share goes up on the weekend even though our ADU goes down. Something that maybe Ken Kovash should speak to.

  10. Are ther any statistics about the use of sunbird ? The statistic of thunderbird users who have lightning installed says nothing about the calendar project.
    In business you will use sunbird an thunderbird (not thunderbird with lightning), I’m shure !

  11. My private usage of Thunderbird/Lightning is much higher during the week, because I use the Portable Edition at my office. Statistics may recognize me as a business user although I use it for private purposes only.