I think it's clear that almost all of the dark traffic is simply https sites. It's no necessarily apps, it can just be gmail...
Someone really should make it a default to pass the referrer even for https.
Someone really should make it a default to pass the referrer even for https.
edit (less obtuse): there should be less passing of referral headers, not more. Browsing is already such a leaky experience privacy-wise, we shouldn't be clamouring for it to become worse...