To clarify what I'm measuring: By looking at the files fetched by portsnap, I can identify (for instance) that a system is updating its ports tree (or rather, a compressed snapshot thereof) from 1AM on August 2nd to 7AM on August 5th. This will count as 3.25 days of updates, and will be counted on August 5th (when the fetching was done). A system which updates once per day and a system which updates once per hour will both appear this way as 1.0 days of updates being performed per day.
Versions 0.9.x of portsnap are those distributed from this website and via the FreeBSD ports tree; versions 6.0 and 7.0 (and more to come) are copies of portsnap from the FreeBSD base system (and the version number refers to the version of FreeBSD).
I generate these statistics by gathering the access logs for portsnap.daemonology.net, portsnap1.freebsd.org, and portsnap2.freebsd.org, and running them through several perl scripts to extract, accumulate, and tabulate the values; I then use MetaPost (and mpgraph) to draw the graph, which I convert into a PNG file using peps.
Note that this is a stacked area graph: The height of each region corresponds to the number of users of that version -- for example, 0.9.3 appears partway up, but the green region is very small since that version of portsnap has very few users -- and the top boundary corresponds to the total usage of all versions combined. This sort of graph is useful when you want to convey the approximate relative size of several contributions over time along with their total.
A couple of blips on the graph which are worth pointing out:
Please send any comments about this to me at "cperciva" at this domain.