Do Digg and Google News operate whitelists?

I spotted an interesting post on Soshable, which flagged up some data that shows how difficult it is for smaller publishers to break through to the Digg front page.

In the past week, according to data gathered by di66.net, the top ten sources featured on Digg are as follows: The Telegraph, The New York Times, YouTube, Time, Arstechnica, Huffington Post, Washington Post, Cracked, the blessed Daily Mail, and The Guardian. All big-ass publishers.

JD Rucker, who wrote the Soshable post, says Digg needs to diversify, unless it wants to die:When less than 1% of the sites submitted control 46% of the front page, diversity is dead.”