Hacker News has pretty clear guidelines, and reasonably clear subject matter:

http://ycombinator.com/newsguidelines.html

Although a lot of people are (IMO) intellectually dishonest in what they really consider intellectually gratifying, rather than simply find themselves strongly agreeing with, or angry about. For instance, US immigration/border policies are something that I feel strongly about, but are they interesting from an intellectual point of view? I don't think so, particularly.