answer:Standing out from the crowd in some way. It doesn’t have to be that that person is objectively interesting, but in that one moment, that person stands out and is interesting because of that. For example, reading the thread with everyone having similar opinions and agreeing with each other, and then one person comes and says something different, points out some detail no one else mentioned, has a completely different mindset that the rest in the thread, or simply says “I disagree” while everyone else agrees. Or when you read fifteen answers dripping with seriousness and get the vibe something real serious is going on and then someone cracks a joke and disrupts the mood. That is what makes that person interesting in that context. Standing out, being in some way original, having different stream of thought and disrupting the mood of the crowd with your appearance, words or behaviour. Make people wonder and confuse them, making them think in another direction. Breaking the monotony. That is what, in my book, makes someone interesting.