“Findings and conclusions: 1. Anti-dark social: t.co links appear to be presenting a referer header when there shouldn't be. 2. Contributing to dark social: comments on Facebook, when clicked on with a WebKit (Safari and Chrome) browser, don't send a referer header 3. Contributing to dark social: chained redirects in Twitter's official app on iOS. 4. In testing links from Facebook and Twitter over HTTPS the referer is present in most cases. 5. GChat links present a referer over https://plus.google.com/ on desktop browsers.” - × × ×