This is definitely a step in the right direction!
Ideally, I’d like to have something that I can set up on my phone and desktop(s), so I can have an aggregate search over all the things I visited, and on whatever device.
Is there a way (architecturally) to make that happen, without having to rely on (say) using one browser on every device?
Doesn’t DNS server only see the hostname instead of the URL? The approach would allow to only scrap home pages then I guess. Also, what about pages behind login?
Correct for the first two, I hadn't thought about that. Could be done by uploading history once every hour but that's annoying. Pages behind a login aren't ideal for this under any approach because they tend to be dynamic.
Memex is not able to do cross-browser/device yet, but we are short before releasing our mobile apps for iOS and Android, as well as syncing between devices.
Both the extension and mobile app will be offline first and sync happens with an end2end encryption via a relay server that deletes update message after every device has been picking it up.