I copied a Reddit post that describes someones impression of the original Pottermore.
"Does anyone remember ~10 years ago (maybe less, I can't remember exactly) when the old Pottermore website was popular...you could go chapter by chapter through each book and discover soooo many hidden secrets in the books. It was like an interactive game. You could gather material in your trunk and when you unlocked certain characters or events, then you had access to the articles JKR wrote. It was so magical and wonderful...the newest Pottermore site isn't quite the same to me. Anybody else remember this and feel the same longing to relive that site?"