[seanlinehan]

It is a legal requirement to allow users to unsubscribe from your email newsletter, yes. What Slack does that is really cool is at the bottom of their notifications email they have:

Snooze these notifications for: an hour, eight hours, a day, three days, or the next week. Or, turn email notifications off. For more detailed preferences, see your account page.

"hour", "eight hours", "three days", "next week" are all links that silence the notifications for discrete periods of time. Pretty neat.