Further details of the identification system used in Windows 98 registration have emerged. In the past few days it has been revealed (see earlier story) that data gathered during the registration process gives Microsoft the means to track both individual users and the documents they produce across the Internet. Each copy of Windows has its own registration number, and during online registration the user is asked to fill in personal details, including name, address and class of user. The registration also produces a hardware audit of the local machine, but the user can decline to send this to Microsoft if they want. In addition, however, machines with an Ethernet adaptor present will send a unique hardware identification number, whether or not the user declines to send hardware audit information. Microsoft yesterday described this as a bug in the software, but the company's privacy policy, parts of which were published here in yesterday's story, makes it clear that it's no bug -- it's quite intentional, and Microsoft has been upfront about it (albeit in a document hardly anyone's going to bother reading). The number is used to generate unique identification numbers for Microsoft Office documents created on the machine. These numbers are embedded in the documents themselves, which means they can be 'fingerprinted' -- ever send somebody a file anonymously? Maybe you didn't after all. If the machine doesn't have an Ethernet adapter, a dummy number is used. This is -- allegedly -- common to all non-networked Windows 98 machines, so it shouldn't be possible to use it to trace documents. But if the mechanisms for processing unique identification numbers exist, then clearly Microsoft is going to make the numbers unique -- unless the appalling publicity puts it off the idea. A unique number system, quite possibly incorporating the Pentium III identifier, is an obvious next step for Windows 2000, particularly as Microsoft wants to introduce universal registration, or possibly even the infamous 'software rental' model by that point. But the exposure of the current tracking system seems to have torpedoed that plan for the moment. Microsoft yesterday said the Windows 98 identification system certainly won't be used in Windows 2000. But we'll all have to watch the process that is in there very closely, just in case. ®