The People's Republic of China, everyone's favorite "communist" superpower, operates a major national filtering system known as the Great Firewall or the Golden Shield, which blocks political, religious, and pornographic sites.
Its effectiveness varies dramatically from ISP to ISP and state to state, implying that ISPs run their own filtering as well as the state controlled blacklist, which is the result of ambiguous legislation creating a climate of fear and self-censorship.
In 2005, Freenet 0.5 had the honor of being blocked by Golden Shield (at the session bytes level). Our website has of course been blocked for very many years. Recent surveys suggest Freenet still has a high level of trust in China, although few people use it, probably because of lack of content. The freenet-china.org website had inserted content onto Freenet 0.5, but it seems to have stopped updating in 2003, and in any case never moved to 0.7 after 0.5 was blocked.
Chinese internet connectivity
Chinese internet connectivity is close to that in the west, apart from Golden Shield. Most users have contracts and it is believed that most of those are unlimited as of 2011. In the past cards were used which allowed a certain number of hours. Bandwidth (for broadband, which is fairly common) is typically between 2 and 8Mbps downstream, and 500kbps+ upstream. Generally file sharing is tolerated and there aren't necessarily monthly traffic issues. All of this probably varies dramatically from region to region and city to city.
With regards to Darknet, uptime may be an issue, for exactly the same reason as in the west - laptops, and people don't leave their computers on. However, peak internet time is 5-10PM, so your friends may be online at the same time as you are. Also, China has only one timezone. File sharing clients often auto-start on startup, so Freenet doing the same thing is not unreasonable. File sharing is often via local sites, which may have political/pornography/etc filtering even if they allow copyright infringement.
More filtering issues
Also, it appears that Tor public entry nodes are now blocked, and some of the bridges too. This means it is likely that Freenet Opennet seednodes will be blocked too if we become more visible. See here.
There have been rumors of a "whitelist" system where if you use more than some threshold of international traffic, your traffic is singled out for special filtering and you can only visit government-approved sites. As yet this is unconfirmed, it may be still in the process of being deployed.
In 2010, the Chinese attempted to introduce a client-side mandatory spyware called Green Dam. After widespread criticism, including in the local press (which usually follows the government line), the government withdrew on this.
Filtering status for our website can be seen here