Various reports making clear that one of the reasons Sobig.F grew so quickly was China. Not because it started there — it looks like it started in a posting to a Usenet porn group — but because so many Chinese computer users don’t know the basics of online self-protection. According to this AFP story, 30% of Chinese Internet users were infected, amounting to 20-mm computers in total. This created a storm of Sobig emails that flooded the region, and, eventually, leaked back into North America. It also explains, in part, why during the outbreak’s initial stages traffic reports showed the worst network responsiveness in SE Asia.