People who claimed that global warming wasn't caused by humans, or that it simply didn't exist, got a lot of possitive diggs. People who claimed that global warming WAS caused by humans, got their comments moderated down to the point of getting a negative score.
Originally, one could think: Ah, many people in digg agree that global warming is NOT caused by humans, so they're modding down their opposers.
But here's the trick: *ANYONE* can become a digg user, just by signing up. So what happens when the almighty buck is involved?
Picture this. Oil companies have astrotufing campaigns (like the "friends of science" website) to throw bogus claims on Global Warming. Obviously they have the money to do that.
So what happens when *ANYONE* can mod down a comment that seems uncomfortable? Since my involvement in the Okopipi anti-spam project I've studied the phenomenon of infiltartion in peer to peer networks, and how some rogue nodes can try to insert chaos into the network. This can happen, and there are many papers in P2P networking dealing with sybil attacks and eclipse attacks.
Picture this theory, it's up to you to believe it or not.
Oil companies hire people to (or tell their employees to) mod down "global warming is caused by humans" comments on digg. They have the means, and the motive. So why don't they? We've already seen astroturfers invade slashdot with their comments.
So, are the oil companies astroturfing digg? We'll never know FOR SURE, because digg is anonymous. But it seems too much of a coincidence, don't you think? My theory is that they ARE doing it.
Let me explain similar events that happen on TV. In my country, there's a news program that has a phone-call enabled poll. Normally the polls look balanced, but when the target of that poll is a political candidate or party, suddenly the number of calls (also shown on the poll) goes up 10 times, and as if magic, the left-wing candidate always gets the preference or the best comment.
In other news, the TV show is vulnerable to UNMODERATED VOTING which skews the statistics. Since the calls are not sent by the TV company at random, but received, the left-wing party (which is in power right now) can as well tell their employees to call the TV show and vote in favor of the party in power. Again, astroturfing.
In the case of digg, what we're dealing with is UNMODERATED MODERATION. Comments can be modded down, but where are the metamods? There is no metamoderation in digg, and moderation is INSTANT.
And that's another reason I like slashdot: To moderate, you need to have metamod experience. And metamods are only given to people with high karma. It's a self-regulated system that depends on the long-term participation of members.
In contrast, the digg moderation system is vulnerable to coordinated attacks by astroturfers.
Conclusion: Even if we aren't sure if oil companies ARE "astromodding" digg, what we are sure of, is that THEY CAN. Therefore, the digg moderation system needs to change.