I am often installing whole new email servers (author of https://poste.io here)... And thats not true, at least from my experience - well unless your first email is not "super promo whatever"...
Does the IP location of the server matter? The guy who wrote the article is in South Africa, if I understood correctly. Note that if the company is outside of the US and wants to keep control of their own e-mail, it would want to have the mail server locally, not in the US. Having the server in the US is otherwise not significantly different than having it in gmail.
Indeed, and at least the typos (like the "interenet") can be easily detected with the free spell checkers (and even some grammar issues!) It can help efesak2, but it's off topic to what we discuss here.