Currently, if a user gets a large number of ignores with some other signals, their posts will disappear from the global pages. This is a work in progress, however. It's our goal to put the majority of filtering into the hands of users, but we will use those signals to pick out content that is far outside the goals of the site. In short: if it would be difficult to find someone that considers the content a reasonable source of thought-provoking conversation, we don't worry about it falling out of the global feeds. It's not our goal to host all content agnostically.
With a poulation of only 6k, it would be very easy for people to trend the kind of content you see on /beatingwomen, /whiterights, or /jailbait. Will that kind of content be removed immedietly?
Nothing official; not yet, anyway. We've all heard the old Potter Stewart, "I know it when I see it." Nudes aren't necessarily smut, and smut doesn't necessarily have to feature nudes. Here's the loose standard mk shared with me once that I would like to somehow formalize, but don't know how, exactly, to do so: Can anyone reasonably think that this content is "thoughtful"? If not, then we don't feel bad killing it (although we probably won't unless it is porn; that's what "ignore" is for). I will say that NSFW content can be acceptable, but certainly not if it isn't labeled as such.
I don't really like subjective determinations like the one established by Justice Stewart. I believe that mk also used the phrase "thought-provoking" rather than "thoughtful." I'd argue that salacious content can easily apply to a strict definition of either "thought-provoking" or "thoughtful," but I'm not the one making that determination. I'm happy to see hubski emerge as a home for diverse, thoughtful discussion on the Internet. I think the true test of this platform is whether that discussion can coexist with a good dose of smut.
As long as the site is small enough that it can be easily monitored by a few of us, porn will be removed as soon as its noticed. That really isn't negotiable. If it grows to a place where its too big to monitor individual posts, then I suppose it will be up to the community to decide what is seen and what's ignored.
Here's a comment where I explain my position in more detail: http://hubski.com/pub?id=49892 Ultimately, I don't think statements to the effect of "We will do this..." are very helpful. The best I can do, is to make clear the type of content that we do support. You can assume that the content you mention isn't included.