Netizens were able to visit Facebook, YouTube and Twitter, for two days

China, with over 500 million Internet users, forms the largest and most vibrant community of Internet worldwide. China blocks most foreign social networking sites (SNS) for fear that unrestricted access will lead to instability in the country. Chinese SNS companies have filled the void in the market, offering similar products that censor sensitive issues.

This week some Chinese Internet users reported that they were able to access those blocked websites such as YouTube, Facebook and Twitter.

“Suddenly I could freely access YouTube! There have been no need to scale the Great Firewall!” Posted by a netizen on social network “Weibo”, a microblogging platform similar to Twitter, which allows users to send short messages and follow other users.

Internet users, including students on college campuses, reported being able to access YouTube, Facebook and Twitter from their mobile phones or desktops during this Monday and Tuesday.

“Yesterday afternoon I used Facebook for the first time,” said a 23-year-old student of the prestigious Shanghai Jiao Tong University.

“I took a look, I’m sure all of a sudden a lot of people registered on Facebook yesterday,” said Zhang, adding that she also created an account.

It is unclear what caused the crack in the Great Firewall. However, on Wednesday, access to Facebook, YouTube and Twitter was blocked again.

Some users in China pay for a virtual private network (VPN) to bypass the block. Over the weekend, Chinese users also have access to the social network “Google +”, and left mass comments on the page of President Barack Obama.

Google + is currently blocked through normal desktop access, but its mobile application that allows users to access the site, has become available in China recently.