A Google feature that warned users about banned or sensitive words was dropped after a protracted battle with Chinese authorities over search.
Google confirmed on Monday that it had turned off the function, citing concerns over user experience.
Campaigners described Google’s decision to remove the feature as “self-censorship”.
The Chocolate Factory announced the feature in a blog post at the end of May last year.
Under the subtext of “improving the search experience”, Google said the new feature would notify users if a keyword is likely to cause connection problems by triggering the Great Firewall’s content filtering system.
Users would then be given the choice of continuing with their search, avoiding any blocks by re-writing the keywords in Latin pinyin script, or following a link to a help page to find out more.
However, not-for-profit Greatfire.org, which monitors censorship in the People’s Republic, has discovered that the service was turned off “sometime between December 5 and December 8”. A help page was deleted around the same time.
“Since Google moved its search engine to Hong Kong in 2010, censorship of its services such as YouTube, Google Plus and thousands of keywords on Google Search has been done by the Great Firewall, out of control of Google,” Greatfire.org wrote in a blog post.
“This latest move was fully controlled by Google and can as such only be described as self-censorship.”
The same post notes that even though the service has been gone for around a month, no-one seems to have noticed until now.
After that URL was blocked again, Google decided upon a new circumvention strategy – embedding the censorship alert function in the HTML of its home page, thus making it very difficult for the Great Firewall to block without taking down the entire site.