Some time early on Tuesday morning someone took advantage of a loophole in the way German domain names are transferred and stole google.de. For several hours users were directed to a blank page on the Goneo ISP.
Under German law a domain name transfer made by anyone is processed unless the the ISP currently holding it rejects the request, something that did not happen for some reason in this case.
Goneo informed the authority responsible for the .de domain who immediately transferred the domain to Favo, another ISP. Eventually the domain name returned was returned to Google. The search engine is investigating how the theft happened.Source