This is a pretty cursory look into some other possiblities of refererless traffic. Given an ordinary browsing session or interaction from an end user, what else could be leading to HTTP requests without the referer header?
Off topic a bit, but I just want to say I like the layout and the general approach of your blog. If it's a template I haven't seen it before.<p>The "pondering" section is intriguing. What if you could accept input as to what topics readers might prefer?
Regarding mis-measuring "dark social": For ecommerce, Pinterest traffic is estimated to be 64% larger b/c of the popularity of the iPad app. This is significant given that Pinterest is now the 2nd largest referral source (depending on which ecommerce sites you are measuring).<p><a href="http://llsocial.com/2012/07/pinterest-traffic-being-significantly-underreported/" rel="nofollow">http://llsocial.com/2012/07/pinterest-traffic-being-signific...</a>