Subject Filters for HN

Rob Malda's interview in the WP made me think: why not filter hackernews by subject matter? He said that he didn't care about the latest version of coffeescript, but wants to know about "Tech Culture" I don't care about Tech Culture at all, but I really do care about new tools and workflows. I also care about NSA/Snowden revelations on different days. Why not have filters or a point system based on whether the article is a "tool", "news", or "tech culture" (actually, you guys probably have a better category system). Then when people give points, the natural filter just aggregates points (what you have now), but people can subtract out "tech culture" points and you get a different feed.