From the FAQ on the page:
What about my data from the old Digg?
We believe that users own their data. We’re working on a system that will extract all user data from the old Digg infrastructure. In August we’re launching an archive website for users of the old Digg to find, browse, and share a history of their submissions, diggs, and comments.
If you’d like to be notified when your data will be available, just enter your email address here[1]. Then stay tuned, and let us know if you have any questions.