Courtesy: NetMarketShare

After just a little over nine months on the market, Windows 7 has already passed Windows Vista usage worldwide based on monthly average. In July, Windows 7 had 14.46 percent, while Vista had 14.34 -- a sad number for being on the market over three years. It's clear that Windows 7 is Microsoft's most successful operating system ever, growing at a steady rate ever since its launch back in October. Windows Vista, on the other hand, is debated as one of the worst operating systems in history. That, or Windows Me. I am using Windows 7 now and can vouch for its success.