POST: Analysis of Privacy Leakage on a Library Catalog Webpage

Eric Hellman ( has written up a recent presentation at the Code4Lib-NYC meeting in which he performed an “Analysis of Privacy Leakage on a Library Catalog Webpage.”

Hellman selected a single webpage for a book in the NYPL online catalog and traced “all the requests my browser made in the process of building that page.” Noting that “my browser contacts 11 different hosts from 8 different companies,” Hellman investigates each company’s privacy policy and use of cookies to give an alarming picture of the way that patron browsing data is shared via cloud-based library catalogs. He concludes:

In 1972, Zoia Horn, a librarian at Bucknell University, was jailed for almost three weeks for refusing to testify at the trial of the Harrisburg 7 concerning the library usage of one of the defendants. That was a long time ago. No longer is there a need to put librarians in jail.

dh+lib Review

This post was produced through a cooperation between Heather Caldwell​, ​Nat Gustafson-Sundell​, Mike Hesson, Jan Lampaert, Heather Martin, Jennifer Millen, Caitlin Pollock, Sarah Prindle, and Chella Vaidyanathan​ (Editors-at-large for the week), Roxanne Shirazi (Editor for the week), Sarah Potvin (Site Editor), and Zach Coble and Caro Pinto (dh+lib Review Editors).