China Blocks Foursquare After Users Check Into Tiananmen Square On It's 21st Anniversary

The Chinese Government decided to block the mobile app service Fourquare after users "check in" to  on the 21st anniversary of the Tiananmen Square massacre. Although Fourquare is new and small compared to the giant web service, Facebook, this event shows a very interesting usage of the web application as a protest vehicle. During the 20th anniversary, other web services were banned as well, including Twitter, Flickr, Blogger, Wordpress and Hotmail.

In memory of the Tiananmen Square massacre
In the summer of 1989, more than 3000 protesters and students were killed by the Chinese government for protesting against communism in Beijing, China. All forms of discussion of the massacre  are strictly forbidden in mainland China.