As you mention with the Wikipedia ref, there was controversy with Google's early attempts to work in China. What happens here is that Google tried to do a "best-effort" service for Chinese users, with the assumption that partial service would be much better than no service (and certainly WAY better than what Chinese users get from their own web companies like Baidu, that not only enforce censorship but also report "bad users" to the government, actively help to spy on dissidents etc.--something Google never considered doing). The search UI would notify users that some results were excluded due to government-enforced restriction, which was at least transparent--and not unlike what Google has to do today in the EU with the "right to be forgotten" censorship. But this wasn't good enough for the PRC, their firewall would impose harsh punishment to users who tried to browse forbidden things; I don't remember details now but it was like: you try to search for certain words, you'd be cut off the internet and not only your IP but other people too. So in a later attempt, Google search tried to warn users in advance, with a customized Google Instant so the user could avoid submitting a "bad" query that could result in blocking. This idea didn't work because the firewall was quickly updated to crack down on it, and I think that was the last attempt, then Google desisted to fight this battle because any progress would clearly require too much compromising, more than could be justified by an attempt to provide a pragmatic, partial service.

[Disclaimer: Googler, but not especially intimate with the events above; none of this is internal info either, it's all widely reported stuff.]