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Yesterday, Digg went down for an hour in the middle of the day. Initially we thought it was an unplanned outage, but it turns out that a number of changes were made to the algorithm that controls which stories are "promoted" to the front page. The changes have started a mini-revolt among the top submitters reminiscent of the community uprising over Digg's deletion of HD-DVD unlock codes last year. We talked to several top diggers to find out what changed, why they're upset, and we have our own theory for why the changes were made.

The main change affects "top diggers," the few submitters who contribute a huge percentage of the stories that make the Digg front page. These users, who have all submitted thousands of stories each, submit more than 10 percent of stories that make the front page of Digg. Muhammad Saleem — known as msaleem on Digg — has submitted 1,201 articles that eventually made the front page. He tells Valleywag that prior to the algorithm change, it would take him between 110 and 130 Diggs for a submitted story to make the front page. Now, it can take more than 200.

A top digger submits a story, it gets 100 diggs and then sits there in upcoming queue for 8 to 10 hours getting 180-190 votes and not being promoted to the front page. Other stories with 40 votes (from newbie users) get promoted from under you. Everyone loses. Good content submitted by top users is doomed to fail.

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Another top digger, MrBabyMan is frustrated as well.

It seems a fairly transparent strategy to clean house of the submitters who have been dominating the front page for a while now. Essentially [they] adjusted the diversity factor to skew against popular submitters. Digg-critical stories are frequently buried before they ever reach the front page.

The lack of transparency at Digg has been criticized before. Diggs (votes for a story) are public, but buries (votes against a story) are not. Rumors abound of "bury brigades" which mass bury articles they disagree with — stories about a particular political candidate or written by a particular website, for example. The constantly changing Digg algorithm has never been made public, though guesses have been made as to what it contains.

Our theory? Digg is attempting to throttle the number of stories that make the front page. As more and more stories get promoted to the front page of Digg — FP'd, in Digg-lingo — stories spend less time in the spotlight. By increasing the number of votes it takes for a story to make the front page, turnover should decrease.

I also spoke to Drew Curtis, proprietor of Fark.com, a semi-competitor of Digg's, about the changes.

Fark is a benevolent dictatorship or as I like to call it, a house party. You can come in and have a good time with the rest of us but if you shit on the floors and tell me my sense of decor sucks and the beer is awful, you're gone.

Digg is like Student Government on any given campus. It's a full-blown governmental institution completely ignored by the administrators, created for the appearance of having a say in what's going on. No wonder there is chaos. Or maybe it's more like Soviet Russia, where you're told you've got freedom and a voice and can make a difference, but you really can't do shit.

Digg's trying to do one of two things, either improve the quality of submissions or drive the pageviews up. I would suspect the latter, once VC gets involved it's all about the money.

Digg founder Kevin Rose posted on the Digg Blog about the recent changes:

as we point out in our FAQ, occasionally you will see stories in the upcoming section with 100+ Diggs - this is evidence of our promotion algorithm hard at work. One of the keys to getting a story promoted is diversity in Digging activity. When the algorithm gets the diversity it needs, it will promote a story from the Upcoming section to the home page.

But Kevin, why won't you make these algorithm changes transparent? Why won't you make public who buries the stories? Why do you refuse to acknowledge the existence of moderators manipulating stories behind the scenes? Isn't "social media" about openness and transparency? Fark has never pretended to be open. There is editorial control behind every story that makes it to the front page.

If there continues to be manipulation and big brother-esque control behind the iron curtain of Digg, the users may soon give up and look for social news elsewhere, taking their pageviews with them. It's an open question, however, whether the masses of Digg users share the parochial concerns of top submitters.

I attempted to reach Digg CEO Jay Adelson and founder Kevin Rose via email. Rose was in a meeting at the time, and has not gotten back to me yet.