Think about the TRA of 96 and what happened with the Supreme Court -- there is, and can not be, a global (or even local) standard of "obscenity". Laws like that are created by legislators (and their lobbyists) that have NO CLUE about technology. The Internet is not property of the US, and in a ferw years English will not even be the dominant language of the WWW. You might also think about whether the internet is a broadcast medium (like tv) or something more private (and initiated by the user, like a phone), or perhaps some new hybrid (?)
Censorship will come to its fruition not through some vague law but by the incredibly invasive actions of corporations (linked to governments) that seek to utterly control the services you have in your home (e.g., pay per listen music, moveis, etc.)