These sites are safe sites though, for example spideroak.com, a well known online file storage service.
How can you be so
sure? How can you trust them when all they've done is proven they own a domain? They went for the cheapest and easiest way out. If they were really smart, they'd go the route of EV. Any Joe can own a domain and read an email to prove ownership.
P.S. I've never heard of them in my 15 years in the industry.