Interestingly, all the technological developments in the use (and misue!) of the Internet are driven by the adult entertainment industry.
Experience has shown that, with the exception of the Washington Post, no-one has successfuly managed to launch and sustain a fee-paying website except for adult entertainment sites.
If the Government does try to censor access by its citizens, they will simply circumvent the restrictions - and you can be sure that the adult industry can, and will invest many more times the time, money and expertise than the government in ensuring that its customers have free access to its goods and services.
If the government wants to score political points and votes (the only reason for doing anything censorship-wise) - it would do well to star with terrestrial television. The scenes of a woman being beaten, and losing a tooth (however inacurately displayed) in a soap opera broadcast by the BBC at 7.30 in tne evening were allowed, and registered barely a whimper. The new Channel 4 show "Whatever" plubs even deeper mines of bordom, and unpleasant aspects of life - but again, it is allowed.
I'm not especially an advocate of censorship per se, but if the government wants to make a difference, it should start by addressing issues closer to home, which are within its remit to alter, rather than trying its swinging "We'lll stop all this ..." attitude which it has probably learned from President Bush's equally ineffectual policies.