I've registered, but haven't gotten my notification yet. Once I do, I'll probably wait another week or so.
I also have no idea how to uninstall Cortana...
I don't have Win10 installed, but have you tried the regular way of uninstalling Windows components?
In Win7 and Win8, you go to 'Control Panel -> Programs -> Programs and Features (i.e. "Add/Remove Programs")
On the left side, you see "Turn Windows features on or off"
You get a window like this:
![00952dd06f.png](http://puu.sh/jicA9/00952dd06f.png)
(Note how I have Internet Explorer disabled/uninstalled)
Cortana is probably the same way. Cortana is either an "application" which you can uninstall like any other application, or it's a "Windows feature" which you can uninstall through the method I just showed, or, failing that, you can probably figure out which services you need to disable in the Service Manager (for example, I disabled Windows File Indexing (or w/e it was called) on Vista).
Sometimes the settings are hidden in other parts of Windows. In extreme cases, you have to muck with the registry.
Yes, technically this is just "disabling" it instead of "uninstalling" it, but it amounts to about the same. And since Win10 already takes less hard drive space than Win8 (in the order of gigabytes), you're still netting ahead even if you can't literally remove the hundred or so MB Cortana takes up.
Cortana and XBox integration are signatures features of Windows 10. It's not clear to me why on Earth they would make those uninstallable.
Because of EU antitrust fines and the USA antitrust lawsuit (both were primarily over bundling Internet Explorer with Windows, and completely missed the real antitrust issues Microsoft was actually doing), Microsoft tends to preemptively make things disable-able.
I don't have an XBone, so that's why I'd disable that (or just hide the icon/app). As per Cortana, I'd feel like a doofus sitting in the middle of the living room talking to my PC (I've tried it in the past, with Vista's voice-control features), so it'd depend on how useful the text-based functionality is. I don't exactly need a personal assistant, but if enough features are actually useful to my needs, I might use it.