Wired had a good article Sept. 30 on the problem of porn spam. I'm getting less of it recently because my univeristy is doing more to filter spam in general, but I still get things that upset me even in the quick glance before I delete them. I'm a survivor of sexual abuse and those images are particularly disturbing to me. It is a desperate feeling not to be able to protect myself from them (and still receive emails from friends who write about difficult memories as part of their healing process).
I'm not a big believer in censorship, but I really wish there was some way to reliably opt out. I started filling out the forms saying I don't want to receive any more mail from a site (even though all the advice is not to do so because then they know your email address is good and will sell it for more money) and I actually think that may have helped more than it hurt. It helped me anyway; it was something I could do instead of feeling completely helpless to stop this stuff coming to me.