[TomGullen]

We put this down to people with JavaScript disabled or ad blockers. CF does filter bot traffic but will capture all hits as it’s tracking through network requests. For us it’s around a 35% increase in what GA reports.

[anderspitman]

For me CF is showing 3x GA unique visitors. Though that's almost all HN traffic, so I suppose it's certainly possible that 2/3 HN users have blockers.