This article in Business Insider is the first media mention I’ve seen discussing the disappearance of referrers on inbound traffic to Web sites. For people who work in analytics, especially on sites that make money by selling advertising, this is a really big deal. In many cases, analytics can be invasive from a privacy standpoint, but referrers generally don’t contain any information you’d just as soon not disclose. Hopefully this will spur a wider discussion of this change.
For what it’s worth, the article is wrong about why browsers strip referrers from traffic that originates on HTTPS sites. When you are viewing an encrypted page, browsers want to make sure that none of the encrypted information is sent over a non-encrypted link. So when you click on a link on an encrypted page that points to a non-encrypted page, the browser strips the referrer to avoid sending information that was encrypted over the non-encrypted connection. Referrers are not stripped when you click on a link from one encrypted page to another, even if they’re on different domains. Sites can get potentially get referrers back by switching to HTTPS, but only if people link to the HTTPS URLs. So if I have a site that accepts HTTP and HTTPS, and all of the links indexed by Google are HTTP links, the referrers will be stripped even if the user ultimately lands on a secure page. So in this case, it’s not really a choice on the part of browser vendors to protect user privacy, but rather one to respect the sanctity of encrypting information.
Update: Also, apparently this discussion of traffic has been going on for awhile.