Can you try hitting searches like http://www.google.cn/images?q=tiananmen directly in your browser? If you’re seeing Google US results with that, then maybe we’re both missing a required parameter. If you can run a good Google.CN search yourself, could you provide me the URL you’re getting?

I don’t think I’ve seen anything definitively describing how Google (or MSN or Yahoo, for that matter) actually implement this. From what I’ve gathered, China’s specific rules about this seem to change on a fairly frequent basis, usually with little historical reference to previous sets of rules, so it’d be interesting to understand the process.

There certainly appears to be some kind of explicit white-listing or preferencing going on with any .cn website, as I believe having that extension implies you’ve had to go through compliance discussions with the PRC government.

But all I’ve got on the “how” of this is pure speculation.

Have there been any articles about how the search engines implement the censorship? Does China just provide a list of forbidden URLs? Or a whitelist of sites that are ok for certain terms (eg only show results for Tiananmen from these 50 sites)?

Going through a bunch of web and image results I’ve found a few omissions from results, different result ordering, and some but not all Western sources are missing. BBC, Washington Post and CBC (to name a few) articles seem to be missing entirely from China results, but you can find the organizations if you search for them directly. Some CNN results still appear, along with smaller news sources or affiliates.

“kim jong il” - web search, notice no BBC or Washington Post
“free tibet” - images, different order
“censorship” - images, naked Dixie Chicks are missing

“sex” - compare SafeSearch on and off in English, and what I think is the SafeSearch radio button in Chinese. China’s two (not three) settings seem to be “Strict” and “Ever-so-slightly less strict”

Interesting that they don’t censor the common misspelling of “tianamen”