A new report released today from the Open Net Initiative indicates that blog filtering and censorship is on the increase in China.

The comprehensive study found that major Chinese blog providers either prevent posts with certain politically sensitive keywords or edit the posts to remove them.

The report also looks at recent blogging history in the country, including reports that in March 2004, the state closed three popular, domestic blog providers, reportedly because a blogger posted a controversial letter regarding the Tiananmen Square incident and the SARS outbreak. Subsequently, all three providers were allowed to re-open, but implemented filtering mechanisms to control content posted to their blogs.

The report also indicated wide spread blocking of blogs hosted on Google’s Blogspot domain.