Key-Systems GmbH seems like a legitimate business to me (judging by their website and company register data), seems they acquired the domain from the Chinese registrar to resell it. Still, seems hard to believe that you wouldn't become suspicious when a Chinese company offers you a very popular domain name that seems to be in active use for sale.<p>That said I've seen registrars make some glaring mistakes in the past and many still rely on faxed documents to authorize domain transfers, so it's not a surprise that stuff like this happens. Often, all it takes is finding out who's the registrar (easy), obtaining a blank transfer authorization form from that registrar (easy again), obtaining the personal or company data of the domain owner (a bit more difficult but still doable), fill out the form and fax it in. Some providers won't even bother to send you a notification when transferring the domain, so like here the legitimate owner won't notice it's gone before it's way too late.