Goodreads offloads DynamoDB tables to S3 and queries them with Athena
I use Goodreads as my main book tracker and reviewer. My impression is that Amazon bought it for whatever reason, and then ignored it. It seems like there's so much more potential to a social community around books than what Goodreads offers. The UI also never fails to disappoint. One of the core user features, searching for books, has all sorts of weird quirks. I'll use a very specific query that should guarantee a hit, and nothing comes up. Or, the book that I want will come up for a second, and right as I'm going to select it, the results completely change and the book I want has vanished.