Giving the impression that people might suffer if they tweet the wrong thing is probably the best that authoritarian regimes can now do.

@Mashka -- While governments can pull the plug on the Internet, it's also a very expensive thing to do, especially for China.  And it has had some serious consequences for Egypt's government.

Temporary shut-downs are one thing but it's sort of like 'cooking off' a grenade -- eventually it explodes in one's face.

Business is just too important to China, and perhaps that's why we're seeing them having the censorship difficulties they are.  Government control and good business just don't mix that well.

That is the scary truth, @Maska. As we've seen in China, Syria, and other countries, it's all-too-easy (and frequent) for governments and dictators to take-down the Internet. Eons ago, dictators controlled the newspapers, then radio, then TV. Now, since they cannot control the web, they just knock it out. 

Thank goodness for people! Sentiment analysis is extremely tricky. It's not only sometimes limited to a country or region - say, Western Europe - but can also be extremely limited to a particular small area, based on a dialect or sub-culture (like your Trekkie allusion, Sharon). IBM's Watson and AI are heading into the direction of understanding, not just crunching, whole worlds of data but it's a really complex task. If this makes censors' jobs harder, then that's a good thing as far as I'm concerned.

But if China really needs to censor something, they do it very simple- they just block the whole Internet- that was happened in November during the Congress of China's Kommunist party- the Internet just "didn't work", most of  Western web sites were not reachable. That's it. Even Skype connection had serious problems.

So... people shouldn't be very optimistic, if the  government wants to censor something, it will do it.

kq4m - Or maybe China is just shooting a shot across the bow, taking down a few words to scare lots of folks.

I expect it's something like that. Only rather than "a few," it's "most." Which can still leave plenty. 

slfisher - And familiarity with those jokes mark you as fellow members of a tribe. Kind of like the time I saw was sitting on a plane during boarding and saw a guy wearing a Trogdor the Burninator T-shirt go by. 

Michael Kassner - I wouldn't call what I hear opinions, although they are anecdotal reports rather than thorough research. If you speak English and have moderate Internet skills, you can thwart the Great Firewall easily. But that applies to only a small fraction of the Chinese  population. And so the censors win. 

It would seem that trying to catch every word, message, and thought is going to be an impossible task as noted by the much less than 100% censorship in China.

Or maybe China is just shooting a shot across the bow, taking down a few words to scare lots of folks. At some point one would think officials would look at the "ROI" of their policies and determine just how effective they are or aren't.