SinisterSal: Well I'll have a go at explaining the anti-censorship feminist position.
Predominantly it's recognising that censorship is bad, and it's particularly bad for women. The history of 'stopping porn' always turns out, very quickly indeed, to mean 'stopping transgressive/LGBT/feminist stuff first'. Information on women's sexual health, contraception and abortion is always targeted very quickly, while the more mainstream porn is often left alone. Pushing a 'banning' agenda leads to putting more power in the hands of the government, which is not going to use it to further a feminist agenda.
Secondly, it involves recognising that a lot of people want to look at, hear, create and perform in sexually-explicit entertainment media and that this isn't wrong. There are a lot of women who want to make sexually explicit media, want to talk about sex, have fun, explore it, play around with concepts of what is and is not sexy. Sure, not all women do, but nor do all women find sex-asentertainment uninteresting or 'degrading'.
Did you see the thread on here the other day about the shock-horror in the papers that Mumsnetters talk about sex? Someone made the very good point that, for some users of this site, discussing what happens in their sexual relationships and being able to talk openly and anonymously about it can lead to them getting help to recognise that their partners are abusive, and being supported in escaping the abusers.
The biggest problem with porn as it is these days is the unsafe, exploitative conditions in which some performers have to work. Unsafe, exploitative working conditions are a big problem across the board (catering, clothing, electronic gadgetry - lots of industries abuse workers, risk their lives, underpay them, terrorize them etc) - activism for better workers' rights is the answer, not prohibition.