Government propagandists, their hired private contractors and useful idiots are creating "downvote bots" or scripts to bury stories which question the government.
Anyone who has posted news items questioning the government's version of 9/11, the government's unquestioning support for Israel, or a host of other topics has probably noticed that all of their recent stories get downvoted virtually simultaneously, which defies the laws of probability.
One free, simple scripting program to create automatic downvotes of certain topics or news posters is called "Greasemonkey", which is commonly used on large social news sites such as Reddit.
For example, there are some 2,480 hits for the google search site:reddit.com greasemonkey downvote. This is some 2,480 times that Reddit users are publicly admitting to using greasemonkey (see also this).
Propaganda agents obviously aren't going to publicly brag about what they are doing, and you can bet that their use of downvote bots is much greater. Moreover, they probably have more sophisticated software than Greasemonkey.
As one example of a publicly-available downvote bot, this script automatically downvotes any stories on 9/11, Gaza, torture, Guantanamo and a host of other topics, downvotes certain posters, and engages in other forms of cyber warfare.
I call on programmers to figure out a way to fight this cyberwarfare propaganda.