chanind.github.io:

I don’t have to do anything to make my app work in the US or Singapore or Kenya or anywhere else, and I didn’t make the Chinese government angry, so it should just work in China, right? Sadly, it’s not so simple. If your app/website servers aren’t hosted from within China, then, for all intents and purposes, it’s blocked. I mean, it will probably technically load, but will be excruciatingly, unusably slow. And sometimes it will just not load at all for hours at a time. This is true for all services hosted outside of the firewall, even in Hong Kong.

Interesting read, full of insight and useful details for folks who want exposure in China.