The "Contributors per month" graph has never made sense to me. Here's an example: https://www.ohloh.net/p/fdroid
So the graph there is currently showing 1 contributor in August, and 2 for (partial) September. (The new 'partial' thing is great, by the way).
However, look above the graph - 30 day summary: 11 contributors, including 5 new contributors. How does that tie in with the 1 and 2?
Any ideas? The numbers still seem make no sense at all. (Currently, on the same project - text says 8 contributors in last 30 days, graph says 2)
I THINK the "Contributors per month" should be looked at as "New Contributors per month" instead. I think it's meant as a gauge of the vitality of a project to show they can still attract new contributors. The confusion with the text vs. the graph is probably in the difference between calendar month and "last" month which won't match except on the last few days of a month and the first couple in the new one.
Still, I could be way off in my interpretation. Hopefully others "reading the mail" will chime in here if I'm wrong.
Ok, yeah, that does seem to make sense. To check, I totalled up the number of contributors graphed, and it came to 64, which is the same (near enough, allowing for my hasty mental arithmetic) as the number of contributors ever.
So it would be great if that title could actually be changed to "New contributors per month". (Although it seems like I'm the only person who's ever failed to understand it?)