I just read that Windows 10 will be available for free for one
year starting from July 29th for Windows 7sp1 and Windows 8.1
owners.

Microsoft desperately wants you to pre register. Why?

Why does it matter if you pre-register or if you don't bother
to register at all?

It's not hardware, like an iPad. It's software. They can source
millions on the same day (they must have decent servers).

So, why bother to "pre register" software?

Is it just a marketing gimmick to add perceived value?