Are you talking about sites who have users in China and are you asking about general connectivity issues or specific issues regarding sites or content blocked by the government there?
There is at least some interesting reading, links to which I'll post in non-linked form in case the content would lead to this board being blocked:
Please note the asterisk which has to be replaced with an "i".
So apparently at least at the time of the study, 2003, blocking sites based in IP addresses was common. Since we have a shared environment here at DreamHost, your site could be blocked on the basis of sharing an IP address with a site that did contain banned content. The prudent, though perhaps paranoid, thing to do would be to host on a unique IP address, avoiding this problem altogether.
Hopefully you'll hear from a bunch of people hosting from China soon. It's morning there so you should get some replies "overnight" if you're in the US.
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