Lightning users on Thunderbird are in the majority for the first time

Three weeks ago, I shared some usage statistics for Lightning with you.

One of the things that I looked at then was the adoption of Thunderbird among Lightning users. Back then Thunderbird 3 users were still lagging behind, but now I can report that on the last weekend, the ratio of Lightning users on Thunderbird 3 was higher than the ratio of Thunderbird 2 users for the first time. Here’s the graph showing the steady increase of Thunderbird 3 usage since November 25th in 2009, when the first release candidate for Thunderbird 3 was released.

As already noted in the earlier article, the ratio of Thunderbird 3 users is much higher on the weekends compared to the Thunderbird 2 users. But even during the workweek we’re catching up pretty fast, even faster than on the weekends.

Interested observers will notice that the graph in this post and the earlier graph differ slightly. The reason is that in the current chart I’ve also incorporated the numbers of pre-release versions, like 3.0 beta3 or

And if someone is asking himself why I only list Thunderbird 3 and Thunderbird 2 ratios here, the answer is that all other versions, e.g. users of Thunderbird 3.1 nightly builds, Thunderbird 1.5 users, SeaMonkey users and people that installed Lightning into Firefox all taken together account for not more than 0.5% of our total active daily users.

I hope that you will find this as interesting as I do.


  1. Alfred Kayser

    Instead of ratio’s using actual would be more informing, as the ratio’s are by nature the precise opposite of each other (when comparing two items only).

  2. Very nice article.
    Is there also any (reliable/statistic) info about the share of Thunderbird users per operating system (OS). I’m very curious in the Thunderbird usage of one OS compared to an other OS….
    (sorry for my bad English)

  3. Michael, operating system stats are directly available from the statistics dashboard at

  4. Hi Simon,
    First thank you for all your hard work. I love your product. I just updated my Thunderbird to version 3.0.3 and when I went to install the Jan 31st nightly builds for lightning and provider I got an error message saying they were not compatible with this version of Thunderbird. Please note that I saved the files to my desktop before installing (rather than clicking directly on the links).

  5. Hi Dan,
    I’d recommend that you install the Lightning 1.0 beta1 release available on
    The code should be identical to the nightly build that you were using earlier, because we didn’t do any further development work on the development branch that 1.0 beta1 was on after it was released and your nightly build came from the same branch.
    More information can also be found here on this blog in this article:

  6. Hi Simon,
    looks interesting, thanks for that. I´m looking for an lightning nightly build running with Shredder 3.0.4b, lightning nightly Jan. 31 does not work with current Shredder…

  7. One line on that graph is a mirror image of the other (Photoshop?) I very much doubt that such a degree of coincidence is correct or possible over a 15-week period.

  8. Greg,
    like I said in the post, only 0.5% or less of our users do actually use something else than Thunderbird 3 or Thunderbird 2. So it’s perfectly reasonable that the two graph lines mirror each other.

  9. Howdy Simon,
    Great article. But tell me: what do these graphs represent? I read the earlier article you mentioned (the one posted a few weeks ago about Lightning usage statistics), and it wasn’t clear to me what data was presented to me in these graphs.
    Are they daily download counts or daily usage counts?
    That is, do they track the total number of times each version is downloaded, or do they count the total number of times each version is run (i.e., does Thunderbird report to a server somewhere each time it’s used to send a message?)?
    Thanks for the clarification.

  10. Phil, the graphs in show both the number of daily downloads (first graphs) and the number of active daily users (second graph).

  11. Is there a decent stand-alone open source substitute for Sunbird (Windows)? Calendars and email programs go together like Jarlsberg cheese and 12 millimetre stainless steel gutter bolts.