Going to the extreme case, let’s say everyone was adding everyone they followed to a list for organizational purposes. Since Agent_M has roughly 1.4 million followers, he’d appear on 1.4 million lists; Marvel would appear on about 43,000 for the same reason. So there would be a perfect correlation between the number of followers, and number of lists you are on.

But as the numbers indicate, only a small percentages of people that follow each account are adding them to a list they create. In this case, if you assume everyone that adds an account to a list is already following that it, 3.4% of Marvel followers have placed them into a list; only 0.1% of Agent_M’s followers have. There must be a reason for that difference.

One possibility, tied to your note, is that perhaps – for whatever reason – people that follow Marvel are more interested in organization than people that follow Agent_M. But I can’t think of an explanation for why that would be.

A more likely one might be that @Marvel is easier to classify. If you look at the lists it is on, words like “comics” and “entertainment” appear regularly. Agent_M might simply be harder to classify.

My current list of hypotheses includes that, perhaps, a higher proportion of @Marvel followers are ACTUALLY paying attention to what the account offers up.

But I think popularity plays an important part here. Given that it appears most people have far less people in their lists than they follow, one could assume they’re choosing their particular favorites based on various interests. Whether or not you cross that threshold is likely to have a popularity component – akin to a best friends vs. friends thing, or strong ties vs. weak ties.