I think it's exaggerated. I am happily running a private mail server on a tiny vserver. My emails get through to whomever I might mail and I do so a lot. I onc

I think it's exaggerated. I am happily running a private mail server on a tiny vserver. My emails get through to whomever I might mail and I do so a lot. I once heard that my email got flagged as spam. Of course, if you don't set up your mail server correctly it might be that it's flagged as spam, but it's not really harder than setting up various other things correctly. It sounds like it was set up correctly by the author. Most people use SpamAssassin, also big companies do. So it should be good. Maybe the network itself wasn't considered to be good by the mentioned big companies.