When we use browsers to make medical appointments, share tax returns with accountants, or access corporate intranets, we usually trust that the pages we access will remain private. DataSpii, a newly documented privacy issue in which millions of people’s browsing histories have been collected and exposed, shows just how much about us is revealed when that assumption is turned on its head.
DataSpii begins with browser extensions—available mostly for Chrome but in more limited cases for Firefox as well—that, by Google’s account, had as many as 4.1 million users. These extensions collected the URLs, webpage titles, and in some cases the embedded hyperlinks of every page that the browser user visits. Most of these collected Web histories were then published by a fee-based service called Nacho Analytics, which markets itself as “God mode for the Internet” and uses the tag line