For example, https://policies.google.com/terms?hl=en says “When you upload, submit, store, send or receive content to or through our Services, you give Google (and those we work with) a worldwide license to use, host, store, reproduce, modify, create derivative works (such as those resulting from translations, adaptations or other changes we make so that your content works better with our Services), communicate, publish, publicly perform, publicly display and distribute such content. The rights you grant in this license are for the limited purpose of operating, promoting, and improving our Services, and to develop new ones. This license continues even if you stop using our Services…”

Use email that is not free. You get a different privacy policy. We have a Gmail account, but nothing confidential and no ePHI (electronic protected health information) ever transmits through that Gmail account.

“But I use a Yahoo account,” you may say. Yahoo, as part of Oath, along with sister companies Verizon and America Online, says at https://policies.oath.com/us/en/oath/privacy/index.html “Oath analyzes and stores all communications content, including email content from incoming and outgoing mail. This allows us to deliver, personalize and develop relevant features, content, advertising and Services… We also may use the information we have about you for the following purposes:

• Provide, maintain, improve, and develop relevant features, content, and Services.
• Analyze your content and other information (including emails, instant messages, posts photos, attachments, and other communications). You can review and control certain types of information tied to your Oath account by using Privacy Controls.
• Fulfill your requests and when authorized by you.
• Help advertisers and publishers connect to offer relevant advertising in their apps and websites.
• Match and serve targeted advertising (across devices and both on and off of our Services) and provide targeted advertising based on your device activity, inferred interests and location information.”

They said “match and serve targeted advertising…” Suppose you play tennis often. Yahoo can sell that information to advertisers, who in turn send you ads and SPAM for more tennis equipment.”

“But I use Facebook, Facebook Messenger and Instagram. They do not monetize information I share with them. They are safe, right?” you may say. According to https://www.facebook.com/policy.php, “We collect the content, communications and other information you provide when you use our Products, including when you sign up for an account, create or share content, and message or communicate with others…. We use the information we have about you-including information about your interests, actions and connections-to select and personalize ads, offers and other sponsored content that we show you.”