Re: Host File
From what I have been told by people who know far more about the telemetry than I do (I block it by not allowing 10 on my PC... problem solved), the Windows Firewall can be used to block the telemetry (so far, at least). While Windows updates could easily change the firewall settings just as they have changed other ones, apparently they don't.
What URLs to block, though, is the big question. There are dozens of lists people have compiled for what domains to block to stop the telemetry, and they're all different-- so which ones are the right ones to block? It's not just one or two... it's dozens of them!
The telemetry MS added to 8.1 and 7 is relatively easy to remove. I've used Wireshark and not found any transmissions that appear to be telemetry... it does the CRL checking, update checking, and other such functions I still allow it to perform, but if it is doing anything beyond that, it escaped my notice. It is possible that I just overlooked it, but at the very least this would mean that the volume of data sent is small enough to not raise an eyebrow of someone specifically looking for it.
I don't know if the same methods can be used to remove the telemetry from 10. In 7 and 8.1, you can just use sc delete diagtrack to get rid of the spying service... it was never part of the original design, so nothing depends on it, and it just keeps on working without it. Maybe it would work the same with 10, maybe not. I would guess that removing the service, which has been renamed to something like connected user experience corporatespeak blather service, would do no worse than add errors to the event log, but I would also guess that there are other processes or services sending data back to the mother ship (Cortana, looking in your general direction) than what you would see on 7 or 8.1. The spying was baked in from the start in 10, not tacked on afterwards like on more desirable versions of Windows.
There were a few other things I did to thwart the telemetry, but removing that service is the most important, and some of the stuff I have read suggests that with this gone, the other deletia are superfluous. Still, I prefer the scorched-earth approach, so long as Windows is still stable. Mine is, with telemetry gone and all of the Metro/Modern apps too (8.1). Rock stable without any of that crap, it is.