The karass is that group of friends from college who have helped one another's careers in a hundred subtle ways over the years; the granfalloon is the marketing department at your firm, where everyone has a meticulously defined place on the org chart but nothing ever gets done. When you find yourself in a karass, it's an intuitive, unplanned experience. Getting into a granfalloon, on the other hand, usually involves showing two forms of ID.
Krebs used InFlow to analyze the network of book purchases surrounding two best-selling titles, one from the left (Michael Moore's Stupid White Men) and one from the right (Ann Coulter's Slander). "What I got were two cliques that were about as distinct as they could be. I kept looking for paths that crossed between them. Every time I tried to follow one of these paths, I'd go out three or four steps, and then boom, I'm right back in the clique." Most strikingly, the two networks intersected only on a single title: Bernard Lewis's What Went Wrong. Otherwise, the two groups were engrossed in entirely different reading lists, with no common ground.
(via FmH)
Having done a little bit of research on academic social networks, there's one major problem with this kind of formal analysis, it can't reveal the actual effect or nature of linkages, merely that they're there. You can do all sorts of fancy spider diagrams about teacher/pupil linkages in intellectual history but they don't show whether there was any influence and if so, whether it was positive or negative.