Sure, but getting this "lingering" metric from 100% of its users already puts them leaps ahead of other social networks. Every user provides clear interaction m

Sure, but getting this "lingering" metric from 100% of its users already puts them leaps ahead of other social networks. Every user provides clear interaction metrics for every content he sees. On the "classic" consumption UI's of other social networks you couldn't create that metric with such high accuracy, because you don't know which content is in focus and the content itself might be static. That's probably also why Instagram's algorithms now put much higher weight on Reels than their classic feed when measuring engagement of a user...