Access to Wikipedia in the mainland of the People's Republic of China was cut off last week as part of continuing Internet censorship in that country. The reasons for Chinese authorities blocking Wikipedia are unknown, but based on previous experiences it is believed that access may be restored in the near future.
Several Wikipedia users from the PRC reported that for most provinces, Wikipedia was blocked starting on 18 October or 19 October. This was confirmed by developer Tim Starling, who indicated that access to both the main Florida servers and the new Korean cluster provided by Yahoo! had been cut off.
A specific reason for the block could not be confirmed. Media coverage in September had mentioned tighter supervision of online news services, but at the time Professor Andrew Lih at the University of Hong Kong expressed doubt that this particular regulation would affect Wikipedia. One report about the current block indicated that it may have been prompted by an order from the "National Security Unit" of the government (possibly the Ministry of Public Security or an agency thereof, but this was not clear). Reporters Without Borders publicly complained about the blocking as "a clear violation of the right of Chinese citizens to information".
Wikipedia has previously been blocked by PRC internet regulators on at least two occasions in 2004. Reporters Without Borders stated that this was "because of dissident political content." However, as with the present block, this claim is difficult to verify; the Chinese Wikipedia article indicates that one incident may have resulted from an influx of users after the shutdown of a political BBS. Lih has also indicated that the PRC does block based on URLs and other methods of filtering, so it would not necessarily need to block all of Wikipedia in order to satisfy its political concerns.
Because of these previous experiences, it seems possible that the situation may be resolved in the near future. Wikimedia Foundation CTO Brion Vibber offered his opinion that the cycle of China blocking and then unblocking Wikipedia will continue to repeat itself. If the present block continues, Wikipedia editors in the Chinese mainland may try to find a resolution by pursuing their case through the government's bureaucracy.