Discourse is a big FU for people who want to read it on the go but don't have mobile Internet. Whereas with HN and phpBB I can easily save the pages offline, Discourse's "infinite scrolling" makes sure you can never save more than a few posts. The 5MB of JS that a single page like [1] forces one to download is just icing on the cake.
https://en.wikipedia.org/wiki/Discourse_(software)