I was talking about embeddings-based search, which is an incredibly flexible and powerful way to find similar content. I still have many ideas about this -- the current [upgraded] search I believe uses something in this direction, but not what I was imagining.

The ability to do embeddings in an embedded fashion, akin to a PKM and w/ a fluid UI, would truly be a game changer. But that's a more challenging design problem, and you could get a long way even without this.