A little while ago Trevor Parscal changed our jsMessage setup to be a floating auto-hiding notification bubble. https://gerrit.wikimedia.org/r/#/c/17605/
The end implementation felt half-baked to me. Since it just swapped text for notification replacement. And didn't support multiple notifications. It even reused the same id as the previous message which was pretty much a completely different concept.
So I spent a night implementing a fully featured notification bubble system. Something that should work for watchlists, VisualEditor, and perhaps some other things like LQT, and perhaps anything we want to start making more dynamic. Same goes for anyone with a good Gadget idea that could use better notifications.
Here's a demo video of the new notification system: https://www.mediawiki.org/wiki/File:Mw-notification.ogv
The changeset is https://gerrit.wikimedia.org/r/#/c/19199/