I also dont get why adding 'utm_source=Robin_Sloan_sent_me' somehow gels with his calculation it is 'an expression of digital etiquette: rather than dump a load of anonymous traffic on your doorstep, I reveal who’s linking'. Theres no actual link to the referring website just some bunch of characters which look like someones name and some of which are in the actual referring URL.

And yeah I'm also thankful also to see that firefox setting.