Facebook, Foursquare and Twitter are not blocked in China… on Blackberry
You cannot browse many websites in China because of the infamous firewall. Facebook, Foursquare and Twitter are some of those affected. Gmail and Google Reader on the other hand are fine.
But when you use the Facebook, Foursquare and Twitter mobile apps on Blackberry, you can do stuff as normal. It’s not disabled or banned.
I tried this first on my Blackberry in Beijing on data roaming then on the hotel’s wifi. Both times it worked. I could upload photos and update my status on Facebook. I could also check Twitter feeds and check into Foursquare.
I also managed to get access on the Blackberry mobile browser. I was able to visit all banned sites on the browser (via wifi). I tried imdb.com, isohunt.com and youtube.com. All viewable.
It might be a Blackberry thing because when I tried it on the Android web browser (as well as Opera for Android), facebook.com and youtube.com both timed out. Facebook app on Android didn’t work either.
This might also be a new development because I appear to be the first one to notice it (although there have been thousands of Foursquare checkins in Beijing so far).