This option allows you to change the default settings for email preferences and forum preferences for all users. These settings are used when a new user is added to the site, and if you find that many users are changing their settings you may want to change the default settings to match the preferred setting for the users.
To access this setting you will need to be logged in as a site administrator and then go to Site administration ► Users ► Accounts ► User default preferences.
Once you have changed preferences to the new setting you will need to click on 'save' in order to make the changes active. Users will still be able to change their own profile settings if the default ones are not what they require. Changing these settings will not alter the preferences for current users on the site.
These default settings are used when someone signs up to your site using email based self-registration, when uploading users via CSV file, and when manually creating a new user.