Read-later apps let you separate reading from finding, since they ideally happen with different mindsets and environments. This is necessary not because browsing aggregators, timelines, and feed readers is given too little time — people happily devote hours to it — but because the goal is to “get through” them and keep checking for new items, keeping readers in a skimming, active, dismissive mindset that’s hostile to attentive reading.
Instapaper’s usage data backed this up: there was almost no correlation between article length and number of saves on Instapaper. People routinely saved everything from three-paragraph Lifehacker posts to 10,000-word feature articles. The most-saved sites were usually just the most popular sites read by the kind of people who knew about Instapaper, not just the longest articles they found.
Nobody was saving Lifehacker posts because they couldn’t read three paragraphs right then: they saved them because they wanted to attentively read them, which wasn’t going to happen in their current context.