The Case for Thunderbird in Mozilla

R Kent James kent at
Wed Sep 16 17:43:29 UTC 2015

On 9/16/2015 8:03 AM, Patrick Cloke wrote:
>> Thunderbird remains the largest open-source email project in
>> >existence, with a total userbase that is larger than some of the
>> >projects that Mozilla considers part of its core mission.
> I think rkent has access to some of these numbers, we should cite that
> here (i.e. we're not just making up numbers). Comparing directly to
> other Mozilla projects might be a bit aggressive, however.

Yes Mozilla graciously added a Thunderbird usage page to the dataviz app 
that tracks app ADI (which is the daily hits to the blocklist download) 
and gave me access. Our usage is recovering now from the summer 
doldrums, back in the 9+ million ADI range, which puts us at an 
estimated active user range of 20 - 25 million. (ADI is a peak daily 
usage number with some users missing, so a factor of 2.5 to 3 is usually 
used to get to active users, with some actual data to back that up).

It's unfortunate that the data from other Mozilla applications is also 
not publicly available, as then we could all work from the same set of 
facts.  But let me say what I can. Three years after Mozilla announces 
what was widely perceived and understood as "Thunderbird is dead", after 
three years of virtually no marketing (including slowly removing links 
to Thunderbird from Mozilla websites), and three years of technical 
neglect, it is truly astounding that Thunderbird usage continues strong, 
both in absolute numbers and in comparison to other Mozilla products. We 
do not approach this discussion about our status from a position of a 
dying project looking for salvation, but from the perspective of a 
product that has held up much, much better than anybody expected three 
years ago. That should really make anybody with an open mind question 
their assumptions about what is and is not important to the internet.


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