That article is very dismissive and pretty flimsy. "A single experiment"? No, it was replicated by multiple people. I’ve concluded that the reason for the mysterious visit is almost certainly innocent.... I’m reasonably certain that address is part of Microsoft’s SmartScreen infrastructure. First, that's not very reassuring. The data should not be readable by Microsoft. Second, since the traffic showed up hours after the message was sent, it is not useful as a screening service. The link would have been clicked long before the URL was checked out. The only mitigating piece of this mess is that the request was a HEAD and not a GET, so they're not fetching the whole contents of the page. But the damage is done long before.