Digg is already heavily biased and I'm pretty sure it's because of astroturfing by political campaigns (Ron Paul, Obama) and ultra-liberal blogs. If you look at the Political section of digg (something that I filter out now), you notice that it's about 99% moon-bat liberal (except for Ron Paul). I believe that studies have been conducted that indicate that liberals tend to spend more time on the internet than conservatives (and conservatives do talk radio more than liberals), but that can't possibly account for this level of bias. Thinkprogress, dailykos, crooksandliars are all *heavily* partisan and continually have stories on digg, and the comments sections for those stories will always shout down (bury) any dissenting view. After reading digg/Politics for months, I highly suspect that this effect is caused by an organized effort.