As can be read on http://about.digg.com/faq it is impossible to automatically delete your account. You should ask them using the webform named on this page.
URLS:
http://www.digg.com
http://about.digg.com/contact
Please note that AccountKiller.com is not associated with the business listed on this page. AccountKiller provides easy-to-understand instructions and guides on how to cancel charges and relationships from the list of businesses on our site, we have no affiliation with these businesses.
Toll free Customer helpline number + (1) *866^ 94O *OOO5^
Call them ;;’.