The Feed Should End
Infinite scroll was never a feature for you. Here is what happens when a feed is allowed to finish.
Every feed you use is infinite because a finite one would let you leave. Ours ends, usually within a couple of minutes, and then it tells you so.
What Ending Actually Requires
A feed can only end if it contains a bounded set of things: posts from people you explicitly added to circles you explicitly made. The moment you introduce recommendations, the supply becomes infinite and the ending disappears.
People Post Differently When Nobody Is Scrolling Past
When your post competes with an endless stream, you write for attention. When it goes to nine people who will definitely see it, you write to those nine. The difference in tone is immediate and it is the whole reason the network feels different.
The Metric We Deliberately Do Not Track
Time on site. We do not report it internally and we do not optimise for it. If someone opens Circles, reads everything and closes it in ninety seconds, that is the product working.
What We Lost
Reach, obviously. Nothing here goes viral, because nothing here can travel outside the circle it was posted to. That is a genuine cost and it is the one we are most comfortable paying.