PED: Apple iPad orders drop sharply
On to the "sexy" curves, click to enlarge (hey, some extra hits due to my title shenanigans can't hurt, and maybe someone somehow learns something new thanks to my mischief).
This one's pretty self explanatory. A nice, round rump evolves after 12 hours into a relatively straight line slightly sloping up. I'll just add that this slope will increase in the next few hours and days, that is, the line will curve in the opposite direction right about now (72 hours) and get steeper, and then it'll become straight once again for some time. Once we get past 100-150 hours, I expect a new, more subtle rump to form in which the slope will very slowly get shallower as the days and weeks pass.
This one's also easy to read. It's an attempt to measure the value of this slope over time (an approximation since I can't actually do infinitesimally small intervals), also called the first derivative, or rate of change. It simply represents the order volume rate per hour. Notice the sharp drop off early on and then it manages to maintain that small value for a longer period of time. The flat part here corresponds with the straight slope upwards of the previous curve.
I'd also like to mention here that I left out a few points that would go in the tiny sliver of space between the vertical axis and that first point up there at 70 thousand. These points would plot much higher, higher than 100, and one of them was over 500 (that is, half a million orders per hour, but of course there never was half a million orders placed, just that the time span during which this happened was a minute or two, so 500,000/60 minutes lasting for a minute or so would generate something like 8-10 thousand orders).
I think this is the coolest one. Please ignore those two outliers at a value of 1, which correspond with that noisy sample I was talking about before. As to what the values on the axes mean, well it's just the logarithm of the same values plotted previously. Something similar would happen if you used log scales on both axes, except the normal values for hours and thousands of orders would show at different spacings.