Notifications can be turned off on the account level in your user settings.
To opt out of all Boardable notifications select the option "Do not send me email notifications." In the settings screen you can also set your meeting reminders and select an alternative email to receive your Boardable notifications. If you want to list multiple email addresses select the "Send notifications to a different email address" option and separate the email addresses by using a comma.
If you do not wish to opt out of all Boardable activity but want to opt out of notifications for a specific discussion or comments on meeting simply click on the Notification Bell from On to Off.