Sometimes, when Slack e-mails me that someone has mentioned me in a channel, and in the e-mail there is content of the message, I have a brief thought of "how d

Sometimes, when Slack e-mails me that someone has mentioned me in a channel, and in the e-mail there is content of the message, I have a brief thought of "how do they know-... oh". I'm slowly getting used to e2e provided by various IMs, as well as encrypted at rest e-mail providers (personally I user Protonmail) - it's not something extraordinary anymore.