Person A posts what seem like obvious questions (until you realise they're not obvious at all, or at any rate some effort is required to articulate an answer). They post their own musings on the questions - what possible answers they've come up with, the relative flaws and merits of each. They're always willing (arguably even over-willing) to acknowledge their own ignorance, and to respond in detail to those comments they get that raise valid/interesting points.
Person B will post questions, too, but they're often phrased more provocatively, and there's little background information on why the question is being asked, or what their own thoughts on the subject are. The usual result tends to be a stream of comments to the original post, but much less in the way of long threads, or follow up.
I respond far, far, better (as may be obvious from my descriptions) to Person A's approach. I'm much more likely to respond to Person A's posts (when I think I have something worth saying) because I feel like my points are going to be listened to, and considered. In responding to Person B's posts, I always have a slight feeling that I am merely providing entertainment. Some people clearly enjoy providing that sort of entertainment - they seem to regard both Person B's posts and their own responses as a form of performance. I'm reminded of the bit in Tom Stoppard's Arcadia - "Rhetoric isn't about being right. They [the Greeks] had philosophy for that. Rhetoric was their chatshow".
I guess there's a place for both approaches. Certainly there are plenty of people who enjoy Person B's style, or Person B wouldn't have such a large readership. But - I don't know - it still puts me off a little, and gives me a more negative reaction to Person B than perhaps they deserve.