I've been a daily Slashdot reader since 1997, and I've been exploring China since March of this year. The only time that I've ever had Slashdot blocked was with the Falen Gong article a couple of months back. Apparently, there was a url keyword detection routine which filtered the page out. Every other page has loaded just fine. Fortunately, since I have a shell account on a U.S. server, ssh -D [port] got around it quite nicely.
I'm not sure how it is in the rest of the country, but here in Kunming, if you run a website, you have to have it registered with the police, which means that someone is probably periodically checking on your site to make sure that the content is considered appropriate and "harmonious." It is definitely a big brother approach, but considering the situation with the cameras in London, Homeland Security in the U.S., and the filtering in Australia, I really can't see an open web besides perhaps a couple of the European countries. To be honest, it reminds me an awful lot of the early gated communities like AOL, only this time, we're dealing with government rather than corporate interests.
Youtube, Dailymotion, Twitter, Facebook, and other such sites are blocked on a constant basis requiring a VPN or SOCKS proxy to get around. It's a bit of an annoyance, but most people around here simply use the native Chinese versions and don't notice anything of the outside world. It's only us foreigners that really know what's going on.
On the one plus side, China Telecom has a 3G mobile data plan with a 100 hour per month limit. I haven't found a data cap on it yet, and I used 17GiB last month watching Stargate: Universe. It's 500 yuan for the adapter and 400 yuan for six months, which works to ~67 yuan, or slightly over $10 per month use. Take that, AT&T!
Whenever I finish exploring here and get to Europe, I'll get a chance to see how all of you fancy Europeans have been haggling us Americans about our data plans and cell phones for years. ;-)