I disagree. It fairly consistent. By your numbers, the computer usage in 2000 is 56 pixels in diameter while the diameter for the circle representing 2008 is 195 pixels. By area of the circle, The bigger cicle (half circle really, would that matter?) is 1212% larger. By diameter, the larger circle is 348% larger. That is a couple pixels (about 3 pixels) or percentage points off (about 5 percent). That is accurate enough to show scale on an infographic in my mind.

As for Hitatchi creating a 1TB drive that holds 1000GB, but later stating that 1TB is 1024 GB, isn't 1 terabyte technically 1000GB which the hard drive companies use, but also frequently used—incorrectly—to reference 1024 GiB or 1024^4 bytes? This other number, 1024GiB is actually a tebibyte, not a terrabyte. They are technically incorrect, but from the standpoint of the majority of the population, the difference between a terabyte and a teribyte is just small print on the back of box. The infographic could be clearer, but honestly, do you think this detail is worthwhile for trying to show the scale of what a petabyte is? That is what, a 5% difference in size? I think that is, when looking a petabyte. If I did my math correctly, there is 50GB of loss (or is that GiB?)

In the end, they are trying to show that a petabyte is a fuck-ton of data. More data than many people can wrap there mind around. They are trying to show scale. How you define the numbers are complicated because we have SI units for both binary and decimal which don't match up and IEC units for the binary side as well. The average consumer isn't going to know or care. They could care that a petabtye is HUGE. The infographic portrays this without trying to bog the consumer down in differences in technical jargon that most of use technical people know but don't bother using correctly ourselves most of the time.