ISBNs are numbers given books by publishers to help uniquely identify them. Every time a new book comes out or a new edition of a book (translation, 2nd edition, paperback, etc) it gets a new ISBN. These numbers are very useful for libraries, book sellers, book readers to help locate books and organize them. Sometimes it turns out that two books get the same number, this problem can turn up in large collaborative cataloging systems like Worldcat. How this happens is a long list of possibilities. Maybe the publisher reused the number, maybe someone miskeyed somewhere, maybe two records got smooshed together incorrectly. It doesn’t really matter, it’s just one of the myriad of metadata problems that can happen.
This Twitter bot posts those ISBN duplicates or collisions. Not to critique or point out errors but to highlight them. Out of the millions of books these two have been connected somehow through this error. A huge system designed to keep things separate occasionally glitches and instead brings them together to occupy the same space.