I wonder if it’d be worth supporting a “webhooks” (c.f. GitHub) system to hit a service when a notification is sent to a user. This would allow email notifications but also interesting things like PushBullet or Growl/Snarl/Prowl notifications
Discourse as Android Application
List of project ideas for Google Summer of Code 2016
Adding “planned” to this, cause we do want to get to this, it is not slotted to any release quite yet.
Right now the #1 obstacle is the service worker update model. Would be solved if we force-refreshed inactive tabs after updates triggered by localStorage events from the new tab.
Assuming I get what you mean: You can claim control of a page from a Service Worker without waiting for a navigation event, see Immediate Claim Recipe - General Usage - ServiceWorker Cookbook
You still need to wait for all the out-of-date tabs to be reloaded, which in the case of someone who always sleeps their laptop and never reboots, may be on the order of several months
As far as I know, you claim all loaded tabs (or none). I don’t know what happens to tabs that are unloaded (only loaded when the user clicks on the tab), but IMHO they should trigger a navigation event and will thus be handled by the registered service worker. But this is a browser/implementation issue, not an API/spec issue.