How to Manage the "Send an email" Option Default

How do I make it so that names aren't checked off to receive an email alert every time I post something? How do I make it so that people don't always receive email alerts?

1. Click on the "Admin" tab in the top right hand corner.
2. On the left hand side click on "Site email settings" and then "Send an email option default."
3. Uncheck the Checkbox and click "Update."