How the use of free email bigs major risks

"the problem is much bigger than any single company. For the vast majority of people, our email system is based on third-party access, whether it's Microsoft, Google, Apple or whoever else you decide to trust. Our data is held on their servers, routed by their protocols, and they hold the keys to any encryption that protects it. The deal works because they're providing important services, paying our server bills, and for the most part, we trust them. But this week's Microsoft news has chipped away at that trust, and for many, it's made us realize just how frightening the system is without it."

From The Verge