Maybe I'm just stupid, but I don't see anything thought provoking.

In fact I feel that a better way to see what redditors are interested in would be to just find (there may even be stats on reddit on this) the ~50 most active subreddits.

If the 50 most active only constituted 10% of all reddit activity, though, they wouldn't necessarily paint an accurate picture of all of reddit.

Maybe nothing could paint that picture, but if there are themes prevalent independent of the subreddit topics themselves, this kind of analysis could shed light on them.