新規ユーザー(および他の信頼レベル)が最も投稿するカテゴリを確認する

That’s something I’d also be very interested in.

Recently I asked a similar question and it seems like out-of-the-box metrics for user interactions are coming soon to the admin dashboard 2.0 :rofl:

Not sure if this specific feature would also be included; perhaps @HAWK might also be able to confirm that.