This is a link to an article at linuxdevices.com (Canonical disputes Microsoft netbook claims) which points out discrepancies with the 96% claim, although it acknowledge that the linux netbook market share is slipping.
*http://www.linuxdevices.com/news/NS5701694759.html
"LeBlanc's claim that Microsoft Windows products, primarily Windows XP, run on 96 percent of netbooks might have been based on December 2008 through February 2009 numbers cited by the NPD Retail Tracking Service. While it does appear to be true that Windows XP has been gaining market share in recent months over Linux, the NPD numbers track in-store sales from brick-and-mortar retail stores, where Linux options are often not available, and do not appear to cover online sales. What's more, the NPD numbers only cover U.S. sales, where Windows predominates, while Linux is more popular in Europe and elsewhere."[...]"If Le Blanc's 96 percent claim is true, it would represent a phenomenal turnaround for Windows. In November, Bloomberg.com reported that Linux gains in netbooks were hurting Microsoft's bottom line, and quoted Microsoft as estimating that Windows products run on about 70 percent of netbooks."[...]"Despite the limitations of the NPD report, other anecdotal evidence, as well as a new study by Ovum, appears to suggest a slippage in Linux netbook market share. Ovum did not publicly report exact percentages, but reported that the Linux netbook share has dropped considerably in recent months. "