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<h1 class="c1">Trends in the fetchmail project's growth</h1>
<p>The scattergram below was made with Gnuplot 3.7 from data pulled
directly out of the project NEWS file using two custom
shellscripts, <a href="timeseries">timeseries</a> and <a
href="growthplot">growthplot</a>. If you see a broken-image icon,
upgrade to a <a
href="http://www.libpng.org/pub/png/pngapbr.html">browser that can
view PNGs</a>.</p>
<div class="c2"><img src="growth.png"
alt="Fetchmail trends graph" /></div>
<p>The graph shows the population growth of the fetchmail project.
The horizontal scale is days since baseline, which is when I
started collecting statistics in October 1996 at version 1.9.0.
Left vertical scale is number of participants. There is one data
point for each release; therefore, the changes in density of marks
indicate release frequency.</p>
<p>The peak in the earliest part of the graph (before the note "Bad
addresses dropped") seems to be an artifact; I was not regularly
dropping addresses that became invalid at the time. Turnover on the
list seems to be about 5% per month (but that's just my estimate, I
don't have numbers on this).</p>
<p>The <span class="c3">blue scatter of squares</span> is total
participants. The <span class="c4">green scatter of crosses</span>
is the count of people on fetchmail-friends after I split the list.
The <span class="c5">cyan scatter of diamonds</span> is the
population of fetchmail-announce after the split.</p>
<p>The <span class="c6">brown scatter of diamonds</span> tracks
project size in lines of code (right vertical axis). The scale
relationship between this scatter and the other three is
arbitrary.</p>
<p>This graph is quite revealing. Several trends stand out:</p>
<ul>
<li>
<p>Over time, the project population displays rather consistent
linear growth.</p>
</li>
<li>
<p>The key event in the project's lifetime was release 4.3.0 in
October 1997, when I declared the code to be out of development and
in maintainance mode, and split the fetchmail list.</p>
</li>
<li>
<p>The run-up to 4.3.0 saw the most intensive spate of releases in
the project's history (the gap in that run happened when I took a
two-week vacation). It was followed by a significant slowdown.</p>
</li>
<li>
<p>After 4.3.0, the developer population remained fairly stable
around an average of about 250 participants.</p>
</li>
<li>
<p>Essentially all population growth after 4.3.0 happened on the
announce list, among people using fetchmail but not active
co-developers.</p>
</li>
<li>
<p>The growth trend in code size looks sublinear, perhaps
logarithmic.</p>
</li>
</ul>
<p>The linear growth trend in population is particularly
interesting; a priori we might expect geometric or logistic growth,
given that the project spreads by word of mouth.</p>
<p>It has been suggested that the linear growth rate is the result
of a situation in which both number of projects and the population
of eligible programmers are rising on trend curves of the same
(probably exponential) rate.</p>
<p>There are some other pages doing similar things:</p>
<ul>
<li>
<p><a href="http://kitenet.net/programs/debhelper/stats/">Here</a>
are growth statistics on the debhelper packaging utility.</p>
</li>
<li>
<p><a href="http://durak.org:81/sean/pubs/kfc/">Here</a> is a page
on the vocabulary of the Linux kernel.</p>
</li>
</ul>
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<address>Eric S. Raymond <a
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