Here's a graph showing the discussion activity levels of FlickrCentral
during the last almost six years. These are four different plots,
shown at different scales:
1) The blue plot shows the number of threads started each month
2) The magenta plot shows the number of responses posted each month, scaled down by a factor of ten. That is, the "almost 900" peak of 8 months ago actually represents 8917 responses in one month.
3) The green plot shows the number of threads that were bumped after being inactive for at least half a year. This plot is scaled up by a factor of 10. The highest value (7 months ago) represents 25 bumped threads in one month.
4) The fourth plot shows the number of threads that were bumped after being inactive for at least a year. Again, scaled up by a factor of ten. Highest value: 19 threads, 7 months ago.
Very clearly, FlickrCentral has seen three bursts of activity throughout its history so far. The first was early on, when flickr became really public and groups morphed from chatrooms to stable discussion groups. The second burst was 33 months ago, December 2007. These two peaks correspond to the times of highest rates of group creation that I documented ten months ago. Back then I interpreted the second peak of group creation as being the result of the explosion of "viral" methods for growing group membership, but now I see that even an established group saw more activity at that time. Well, maybe it was (at least in part) activity complaining about the new types of groups. The more recent activity thrust was in early 2009, right after the previous analysis.
It is curious but not unexpected that thread bumping activity follows global activity, and is slightly delayed after it. Makes sense: the group bursts into activity, many people post and participate, and some go hunting for ancient threads and revive them.
In terms of starting new threads, the graph is curiously different. The first two peaks of activity are clearly there, but the third burst (early 2009) was not accompanied by much novel thread creation. In fact, the number of new threads appears to have declined quite linearly during the last two and a half years.