We don't block porn, but it hasn't been a problem yet. In the past, when people have posted artistic nudity, they've usually put "NSFW" in the title. We generally take the Classical Liberal (Libertarian) approach of not censoring anything, but allowing each user to block the tags and other users they want. So, if someone started posting porn, you could block them yourself. Generally. We reserve the right to censor. Freedom of the press is guaranteed only to those who own one, as it were. People also tend to add community tags as appropriate. So, if there started to be a porn community, it's likely everyone else would start community tagging with something like #nsfw, and you could block that tag. And Hubski is small enough, you could easily block every user in this hypothetical community, if a tag didn't arise. But no promises. That's what liberty means. ^_^