Web censors got their signals crossed in China and Denmark this week.

Users at an Internet cafe in Beijing last May. (LIU JIN/AFP/GETTY IMAGES)

In Denmark, however, Internet freedom went in the other direction. Danish police said a “human error”caused thousands of Web sites to be blocked in the country on Thursday, including Google and Facebook, reported file-sharing news site Torrentfreak. Users who tried to access those sites got a message saying Denmark’s High Tech Crime Unit had blocked the page because the user had offered child pornography. The problem was reportedly fixed several hours later.

Web censorship, a hot topic around the world, is becoming harder for governments to enforce.

In India, Internet companies recently refused a government request to screen and remove what it deemed offensive content related to political leaders and religious figures.

During Iran’s partial Internet blackout last month, Iranians used proxy servers10 times more than they had in 2010.

And when China suffered a major train crash last July, government censors forced the media to stop reporting online about what had gone wrong — but users on Weibo, China’s Twitter, soon filled the news gap.

According to Google’s Transparency Report for the first half of 2011, democracies and authoritarian governments alike made repeated requests to Google to remove certain online content from its services. Sometimes, the government believed the content was a threat to national security. Other times, the reason given was “defamation” or “government criticism.”

Related reading:

Web censorship moves to democracies

What Internet censorship looks like around the world