Utilitarianism is, in my experience of discussing in it, a fairly controversial topic, so I'm probably just inviting a flame war, but I'd like to know the overall stance of B12ers on it. For those who don't know, utilitarianism is an ethical system where the only good is pleasure, and the only evil pain/suffering, and the morality of all actions derives from that. For example, vandalism is wrong because the minor pleasure you get from performing the action is less than the (also minor,but less so) suffering of those who have to clean it up and those who's property is damaged by it. (Or at least, that's my interpretation) Expanding on that further, it states that pleasure and pain are worth the same amount no matter who the individual is experiencing them, and that there is some direct comparison of the two quantities that can be made.
To explain the poll choices, strong utilitarian means you endorse the whole system, whereas weak utilitarian means that you believe that maximizing benefit while minimizing harm is a good, but incomplete basis for an ethical system. The other two should be obvious.
Personally, I would consider myself a weak utilitarian, as, in any given case, if there's a choice between causing pleasure or pain, the pleasure is obviously the superior moral choice, but I believe there is some intrinsic value to knowledge. I can't really explain the latter point, except that I feel morally repulsed by those who are willfully ignorant, though in utilitarian theory they are performing at worst only a minor act of harm( as such individuals would likely not have significant potential in any case).