On: 80% of my traffic is excluded from Google Analytic...

[asadkn]

Firefox has built-in tracking protection since a while and would block Google Analytics. Similarly, Adblock extensions would also block GA (usually behind a strict setting).

Considering we're talking HN visitors, this wouldn't be representative of visitors in general.

[jefftk → asadkn]

Firefox doesn't block analytics in its default configuration; see https://news.ycombinator.com/item?id=27792881 above