Also tosh about "the way Microsoft want you to use it". Every PC is a domain member. If you are using NT, 2000, XP, Vista or Windows 7, it is a member of at least one domain - itself. A standalone PC has a domain SID generated during Windows installation.
I'm afraid it's you that is spouting tosh there, Simonta.
MS define a Domain as having at least one Domain Controller (i.e. share a central directory database). The only time a single computer can be a member of a domain is when it is itself a DC.
Windows Computers standalone or networked without a DC are in a Workgroup.
Indeed, many versions of Windows CANNOT ever join a domain - WinXP Home, all Home versions of Vista and the same for Win7.
Finally, just because a SID is used doesn't make it a "Domain SID". All windows PCs use SIDs, whether they are in a Workgroup (with only one PC or several) or in a Domain.
SD