I have a Gmail account (mostly because I have an Android phone and a Google account is required for updates to the device), which I use mainly for news alerts. It is not my primary email address and I do not share it with others except by accident. (That is, when I’m using my email client, I sometimes accidentally compose a message when the Gmail account, as opposed to my primary email account, is in focus.)
The IMAP interface for Gmail includes a mailbox labeled “Important.”
I have observed that the emails which Google considers to be “important” to me are invariably not.
Indeed, in this case, Google is never right and always wrong.
Frankly (I do everything frankly), I find it rather gratifying that their algorithm is not infallible.