This afternoon, the blind lawyer/dissident Chen Guangcheng left the US Embassy, where he had sought refuge after escaping illegal detention in his home village in Shandong. Chen is currently undergoing treatment at Chaoyang Hospital, accompanied by US officials and his family, who have been freed from their detention in Shandong and brought to Beijing to join him. The foreign press has been all over this, but official Chinese wire service Xinhua also released a statement condemning the US and saying that Chen had left the embassy "of his own volition."
The term " left of his own volition " provides us an excellent opportunity to observe the way Sina censors handle the spread of information on Sina Weibo. "Left of his own volition" is a pretty specific phrase that isn't likely to come up randomly in weibo posts all that often. And since we know exactly when the Xinhua story was released -- 15:41 -- we can track discussion of this phrase more or less from its inception using the search function on weibo, until it becomes a blocked search term. What we found is that while Sina did not block "left of his own volition" as a search term -- searches for blocked terms result in an error message -- the company clearly took steps to smother discussion of the term by disabling the indexing of new posts containing the term. What that means is that while you can still search for posts with "left of his own volition," you will only see results from before 16:50 this afternoon, which is approximately when Sina blocked the indexing. To a casual user, it would appear no one is really using the term anymore; it looks like people are no longer talking it. But make no mistake, the "silence" is artificial; I intentionally used the phrase in a weibo post of my own to system at 16:50 and found that my post did not appear in the search results. I call this "search smothering," and it's a tool I've seen Sina use increasingly over the past month or so as a way to play down discussions of sensitive topics and make it appear they aren't happening. People can still make posts using the term, so they don't feel their voice is being censored, and searches aren't actually blocked so they aren't reminded discussion is being censored, but public discussion is being hidden from them just the same. It's quite clever, in an insidious sort of way. If you're wondering why bother, in this case, I suspect Sina began smothering the search because posts using the term were increasing rapidly as time went by. Before the Xinhua news release, posts using the term "left of his own volition" were coming in at a rate of far fewer than one post per minute. But as the news spread, uses of the term jumped and the posts-per-minute rate increased more or less continually over the next hour. I was keeping an eye on this and tracked the activity in the graph below; it should be pretty easy to see when the smothering went into effect: It does appear there are ways to slip posts through the cracks. This post, for example, came in after the smothering went into effect, but it uses the traditional characters (rather than the simplified ones commonly used in mainland China) for the word "left" and thus appears to have crept through.