I just published my first Webapp (Flowdock) with the Webbapp generator.
Now my question is how to enable notifications sent by this app. Flowdock supports desktop notifications. Is it possible to show them up on phones?
Not sure though, what is necessary to use or activate this feature in a Webapp. It may be that you need to set a security policy in the .apparmor file of your project. My bq Aquaris E5 shows a push-notification-client policy that is available for selection.
Update: David Barth explains on the ubuntu-phone mailing list that "Push notifications for webapps is not supported yet" (Fri, 14 Aug 2015).
There's "web notifications v2" and "push messaging" (i.e. real push notifications), either one developed in a separate branch. Looks like there is some "Ubuntu end-point" that your server needs to send messages to, which will then show up on clients registered on Ubuntu Touch mobile devices.
If you control both ends, ie you develop the webapp frontend, and manage the server as well, then you will be able to receive client registrations, route messages down to the Ubuntu end-point and to the individual devices and end-users.
How to use the "Ubuntu Push Server API" (as part of the push notification framework) is described at the bottom of the Push Notifications Server Guide.