The good data quality is actually an artifact of humans being involved in every step of the cataloging process. There's a large group in goodreads called the GoodReads Librarians, and that group has around a hundred thousand dedicated people who go through and flag anomalies, correct titles and indexes etc
Book publishers or people who've worked in book publishing will know that the book database is one area you don't want to mess with unless you know what you are doing. ISBN's are not the be all and end all of the story, and when you start taking into account special editions, covers, ebook editions, language translations, you'll start to realize that the Book Catalog system going back in history, including Dewey decimal system is a marvel of human achievement.
Of course establishing a good quality index is going to take work. People often forget that quality take human work and effort.
EDIT: I lied. I changed the number from my original estimate of a "few hundred" to "hundred thousand". The Goodreads Librarians group has 103718 members as of when I just peeked now - so it's actually a large number of humans submitting fixes to their catalog.
Book publishers or people who've worked in book publishing will know that the book database is one area you don't want to mess with unless you know what you are doing. ISBN's are not the be all and end all of the story, and when you start taking into account special editions, covers, ebook editions, language translations, you'll start to realize that the Book Catalog system going back in history, including Dewey decimal system is a marvel of human achievement.
Of course establishing a good quality index is going to take work. People often forget that quality take human work and effort.
EDIT: I lied. I changed the number from my original estimate of a "few hundred" to "hundred thousand". The Goodreads Librarians group has 103718 members as of when I just peeked now - so it's actually a large number of humans submitting fixes to their catalog.
https://www.goodreads.com/group/show/220-goodreads-librarian...
If you take a look at the kind of discussions taking place, those are the kinds of things any competitor to Goodreads needs to know about.