The graph is misleading. The "Windows PC" peak corresponds exactly with the release of Win7 -- it is now simply back to normal pre-Win7 levels. But even worse,

The graph is misleading. The "Windows PC" peak corresponds exactly with the release of Win7 -- it is now simply back to normal pre-Win7 levels. But even worse, the authors arbitrarily combined iPads with Macs. Putting the iPad by itself (beginning at zero units sold) would yield enormous growth rates not fit for comparison with Windows PCs. The sudden launch of the iPad makes for a deceptively large growth rate increase. After all, if the iPad were instead considered a "Windows PC", the "Windows PC" line would hardly increase at all. So, pairing the iPad with a smaller category (macs) allows for a seemingly huge growth rate increase. (The macs are in fact such a small category that the "All PCs" growth rate hardly increases even given the huge "Apple only" increase.)