[rodion_89]

Their robots.txt file clearly asks to not be crawled at all.

  User-agent: *
  Disallow:

http://digg.com/robots.txt

[blauwbilgorgel]

Incorrect. To configure your robots.txt to not be crawled at all use:

  User-agent: *
  Disallow: /

Allow indexing of everything with:

  User-agent: *
  Disallow:

It seems they are at this very moment struggling to change things.

[rodion_89]

You are totally right. Disregard everything I said.

[chenster]

Disallow nothing -> allow everything.