You can manage your email subscriptions using the link at the bottom of every email we send, as well as from your Settings page.
Using the link at the bottom of the email
Locate the email in your mailbox and scroll down to the bottom. Press the Unsubscribe link where the arrow is pointing. This link will take you to a page where you can decide which specific types of Khan Academy emails you'd like to unsubscribe from.
From your Settings
Below the email subscription is enabled. An email address is visible. To disable it, click the button next to Enable email.
When it is disabled, it will appear as it does below. No email address is visible. Click the button next to Enable email to re-enable it.