The systems that actually feel like a second brain flip that: they push relevant history, decisions, and prior context at you before you ask, and — this part matters more than people give it credit for — they show their work. Cite where a given answer came from (which note, which meeting, which thread), not just serve up a synthesized blob. Looking at the pushback in this thread (the harvesting claim, the "zero chance I trust cloud SaaS" comments), I don't think that's really an objection to always-on capture — it's an objection to opacity. People will tolerate a lot of passive collection if they can see the receipts on what it's doing with it and where an answer traces back to. Local-only storage helps with the trust problem, but provenance is what actually earns it over time.