You can delete your entire accounts. After the account is deleted your profile information and private messages will be deleted, and other content you created will be anonymized.
You will be clearly informed about what will happen to your personal data after the account has been deleted.
In order to delete your user account, you will need to choose the 'delete account' option on the cancel account page. You can reach this page via the cancel account button on the settings page.
Your user account will be deleted after you confirms this action via the link in the confirmation email.