Digital Stimulus: My only fear is that somehow, they’ll attempt to make it work by turning the Internet into a tiny, manageable bonsai version of itself, carefully tiered and controlled by a mixture of governmental oversight and de facto monopolies in content distribution, the way movies worked back in the days of the studio system (when studios owned everything from the lots to the actors to the movie houses showing the films).
This wouldn’t work entirely because the geeks already have the tools to circumvent it, but it would create a distinct class structure between those who know they can circumvent it and understand the tools well enough to use them, and those who don’t and therefore languish in a heavily-censored realm.
(As a side note, it’s interesting that nobody seems to advocate a ratings system for books. All of the reasons it’s a bad idea for printed matter can be applied to any other medium.)
Books are currently a protected class. 
Books are a known quantity; video games, movies, TV shows and websites are new (at some point) to people and what’s new is not always understood, therefore feared.
I think the immediacy of access to more or less anything on the internet makes it a bit different.
I could look up a dozen different nasty or dangerous things in half an hour, what’s more, without telling anyone what I was doing.
To do the same thing with books would possibly take a couple of days scouting around libraries and dodgy shops, as well as facing the potentially embarrassing stumbling-block of talking to people (librarians, sex-shop owners, explosives dealers, etc) about what I really wanted.
I’m not building that into any kind of argument pro or con web censorship, but I think it’s a notable difference. I can casually drift into looking at things on the web that would just be too much effort any other way.
Mangetout: OK, that’s true. But it’s also true that you can walk into just about any public library and read books about the kinds of things would-be Internet censors want removed from the Net. As long as you don’t check anything out you don’t have to make face-to-face contact with anyone, and even if you do check out a book the contact is absolutely minimal. The sheer variety isn’t there but given the kinds of things real-world would-be censors are up in arms about, there’s enough there to make them very angry.
Dunno. I’m pretty sure my public library doesn’t have bestiality porn (or any other kind, AFAIK), detailed recipes for explosives, instructions on how to cheat at drugs tests, scam people etc - and even if it did, that’s still considerably more effort and time to access than the net (which probably means the average person would not be exposed to so much of it, even if explicitly seeking it)