They would have to appear when I'm not on the site, the same way YouTube's do. I'm not sure that's possible though, and I've not seen a single client do it. Primal possibly could, since they do a lot of the work server side.
Discussion
nostr:npub1jlrs53pkdfjnts29kveljul2sm0actt6n8dxrrzqcersttvcuv3qdjynqn thoughts?
would it be possible?
I believe so, I've never done push notifications myself though. I have the impression that they're flaky on web apps.