It's cloaked so only google can see it - try changing your user agent to match googlebot's.
User-agent: *
Disallow:
This robots.txt should allow all bots to search the entire website. However, I think Google also penalizes websites that serve different content to googlebot than to non-bot user agents. Sitemap: http://blog.digg.com/sitemap-pages.xml
Sitemap: http://blog.digg.com/sitemap1.xml
User-agent: *
Disallow: /private
Disallow: /random
Disallow: /day
Crawl-delay: 1