Here's the deal - if you wanna run a exit node for tor, I'd strongly recommend that you implement your own safetynets - as well, a simple example - remove all the porn... Since you get the pure information flow, traffic-restricting this in the sense of "removing not-so-etical-content", I see no problem with it, because it's not part of the tor filosophy to allow access all things in that sense, it's to remove sensorship. Yes yes, one might argue that "well, now you are restricting it!" - not really. You are safekeeping your interests and makes sure that you can without having a cup of paranoia everytime you fire up the exit node, that you servre the tor user a legitime at better internet - protecting both of you ;).