The September one is a cute idea, but how many shutdown things immediately had a bunch of interns? For example, with Knol, there weren't any site updates or functionality changes for something at least a year before the final shutdown announcement went out, so how could that have had anything to do with interns? The spike in September is so huge I'm not sure interns explains it.
Maybe people are going on vacations (not necessarily Burning Man) and returning with renewed perspective and distance from things and are more willing to close down things. Not sure how one could test this...
I'm happy to report that I have successfully forgotten exactly when perf happens. There was one supposedly optional perf and one supposedly non-optional perf per year. I'm not sure exactly how that would affect cancellations of projects, though.
One thing I do remember seeing was a LOT of half-baked crap being foisted upon people (especially internal customers) because the end of quarter was approaching. Someone had to make their OKRs, and they didn't care how...
Maybe people are going on vacations (not necessarily Burning Man) and returning with renewed perspective and distance from things and are more willing to close down things. Not sure how one could test this...