Earlier this week, SoundCloud sent a mass e-mail to users about an upcoming update to its e-mail handling procedure. Previously, SoundCloud only sent certain account notifications to an account’s primary e-mail address. Once this change goes into effect, those notifications will also go to secondary e-mail addresses. From the e-mail:

Beginning October 20, 2015, all notifications surrounding your account’s security will be sent to all email addresses associated with your account. These notifications include password recovery emails, notifications related to email changes and confirmation of account deletion requests.
Currently, these notifications are sent only to the primary email address associated with your account. At SoundCloud, we take security very seriously—we are making this change to make sure that you will always be notified when important or unauthorized changes have been made on your account. To ensure that you can always get back into your account, you can then use any of your connected email addresses to sign in.

The notifications that will be sent to all e-mail addresses include:

• Password recovery messages
• Notifications related to e-mail changes
• e-Mail addresses added to your account
• e-Mail addresses removed from your account
• Confirmation of account deletion requests

By default, SoundCloud sends all notification to an account’s primary e-mail address. Those notifications could include the ones listed above. But it’d also contain less critical correspondence, such as newsletters, etc. I’m guessing SoundCloud extended these more important notifications to secondary addresses because a lot of people tend to ignore most of the e-mails they get from the services they use. Sending these more-important notifications to all of an account’s e-mail addresses should help to ensure the security of all SoundCloud accounts.