Google and China don't necessarily get along too well. To read about their history, start here.
Google's lastest revelation about their relationship is not shocking but extremely revealing. In short, when you search on Google in mainland China, certain queries will automatically make the search engine stop loading. It will look as if Google is down or the internet is down and last that way for 90 seconds until it resets.
Here is a video demo by Google of the behavior:
Google says they investigated their systems and these issues are "outside Google's control and unrelated to Google's technology."
So to make for a better user experience, Google pops up a message when one of the hundreds of thousands of keywords that may trigger these disruptions to help the user understand why the search is not working:
The message gives the searcher the option to search anyway or edit their search plus provides a link to an explanation.
Pretty revealing stuff.
Forum discussion at Google+.