To wit, the EULA for the full retail version of Windows 7 states on page 9 in section 17, part b: "Windows Anytime Upgrade Software . You may transfer the software and install it on another computer, but only if the license terms of the software you upgraded from allows you to do so . That computer becomes the licensed computer. You may not do so to share this license between computers."
Furthermore, in section 16, part b: "Windows Anytime Upgrade License. If you upgrade the software using Windows Anytime Upgrade, your proof of license is the proof of license for the software you upgraded from , your Windows Anytime Upgrade product key and your proof of purchase . Proof of purchase may be subject to verification by your merchant’s records."
Also the EULA for the OEM version of Windows 7 states on page 9 in section 20: "SUPPORT SERVICES. For the software generally, contact the manufacturer or installer for support options. Refer to the support number provided with the software. For updates and supplements obtained directly from Microsoft, Microsoft provides support as described at www.support.microsoft.com/common/international.aspx."
This means that Andre was only half right in his first response to my question: yes purchasing a Windows Anytime Upgrade does entitle me to support from Microsoft (as the WAU supplement was purchased directly from Microsoft and not the manufacturer of my computer) but the license for the WAU does not replace the OEM license, but supplements it: the original operating system and the upgrade each have their own separate licenses.
"The Anytime Upgrade does not come on a disk, it is just a product key." This is the only direct, succinct, and unambiguous answer I've received to any of my questions. Thank you, Andre.
This also means, per section 17 in the RETAIL version EULA, that I would need to purchase a full license to install Windows 7 Home Premium to install on a "new" (i.e., with a different model or version motherboard if the computer is out of warranty) computer, but the license for the WAU would transfer just fine, because they are two separate licenses. I emphasize retail version because that is the only version of the EULA where this distinction is made--precisely for whom it is irrelevant: people with full licenses can transfer their software to any computer they please, so long as they take if off the old one first.