Um, I live in it?

Why? Because porn is bad? 

It doesn't do anything. Nothing 'happens'. And this block already extends to 'self-harm' websites. Next up: terrorism. Or the BNP. Or sites suspected of copyright infringement (thepiratebay already being nationally blocked). My problem with this is not porn access, because of course there are good ways around any block.

You could always use mobile Internet.

It's not really about me! I have a problem with it even existing even if it doesn't affect me at all. Imagine if the First Amendment was repealed, that's the situation we've been in for a while (see: arrests over Twitter jokes, children being taken away for UKIP support, libel burden of proof on defendant. All of these things would be much harder to do with something like that.).

What happens when the filter is activated? Is it possible to deactivate the filter? Can you answer "yes" to having children but still be able to watch porn as an adult? And who decides what sites are being blocked or not?

We don't know any of the details beyond what Cameron wrote in the Daily Mail. The Mail's editorialising is known to be right-wing biased so ignore any non-direct quotes. So it could be very bad, or trivial.

Axolotls are the cutest thing ever <3 <3

I don't get it. Why do we protect children from natural acts like seeing sex but act completely oblivious to the violence they see on TV. What is really worse? Violence or sex?

I don't think it's too horrible, although i'd feel more comfortable if it were opt-in than opt-out. It's not a bad idea to make ISPs have a porn filter be an option, but having it be the default option is going to cause some problems, especially because, yes, web-filters are often overzealous (i remember at my high school i couldn't access video game forums because they had the "game" keyword, and the school wanted to block flash-games and the like, but caught all video-game related stuff in the meantime)

To be fair, the British have been less hypocritical in that regard. They've been after violence for a while (like much of Europe) and less after sex.

You definitely see more penis on British television I have to admit. Though since what passes for pornography these days isn't very good it ought to be R18 to protect kids from being put off having sex.