addyo@, samccone@, and slightlyoff@ gave talks at Chrome Dev Summit last week about exactly this topic (and plugged Preact while they were at it). The average

addyo@, samccone@, and slightlyoff@ gave talks at Chrome Dev Summit last week about exactly this topic (and plugged Preact while they were at it). The average load time on mobile right now is 19s. (I think they were citing a DoubleClick study.) The Chrome dev rel team is in the midst of a big educational push around these topics right now, because pages are getting more complex, but median devices and networks are actually getting slower as more low-end devices enter the market. As I recall, one of the other stats they cited is that mobile traffic is outpacing desktop traffic, so unless you're designing an app that really only works on a large screen, your users may be more mobile than you imagine. Facebook is a desktop site (most of their mobile traffic is in native apps), so they don't have the same incentives to optimize React for mobile that other developers might.