About 4,500 family and business web sites were wiped out last month as the Canadian government tried to contain an elaborate hoax. The Yes Men, a lefty activist group, produced a series of fake press releases at last December’s Copenhagen climate conference announcing Canada was setting ambitious new carbon emissions standards and pledging billions of dollars in aid for Africa. The release directed reporters to the fake websites enviro-canada.ca and ec-gc.ca (the real website for Environment Canada is ec.gc.ca). Environment Canada promptly moved to have the fake sites shut down. However, Serverloft, the German Internet service provider to the Copenhagen-based company which was hosting the fake websites, ended up blocking an entire set of IP addresses, wiping out thousands of innocuous sites in the process.