Do Facebook and Twitter actually lead to sales? Presumably no-one is specifically looking for information about your book on either of those, so you'd be foisting yourself into peoples social circles specifically to pimp the book. I think the Chinese government policy may be correct in this instance.
Getting people to review it on the sites selling it would be much more useful, I'd have thought.
I don't really like people so the social networking wotnots have largely passed me by and I could be talking balderdash. I do quite like Youtube though. You could get someone to put up a promotional video for you on Youtube. You don't need to access it directly yourself. A simple trailer, talking to camera explaining what the book is about, and then you get attacked by an animal or hit with a rake. Or both, but hey, we're not talking JK Rowling here, so probably best to take baby steps for the first video. Pick a relatively innocuous animal. I'd go for a goose.
Or the reviews on Amazon. Either/or.