@anonymous Yes, I understood you correctly about using widgets instead of some notifications, but what I said is that we only want to have applications and notifications, and not add other types of things for the user to interact with, such as widgets.

@bombo New notifications show up one at a time. As long as you are interacting with the notification that is showing, we queue the rest. You can move on to the next notification by clicking Esc or (soon) the Down arrow. We’ll eventually have an indication that more notifications are being queued.

@zsoltsandor The system status indicators in the top bar include the one for Bluetooth:
http://live.gnome.org/GnomeShell/Design/Guidelines/SystemStatus/Bluetooth
Other devices, such as USB sticks, will be represented in the dash (left vertical panel) in the Overview and their detection will possibly be accompanied by notifications.

@Bla bla bla The described notification system is one of the integral parts of GNOME Shell, and the rest of it might be better than you think . If you haven’t tried it lately, building the latest version with JHBuild might be an interesting thing to try:
http://live.gnome.org/GnomeShell/#Building
The design is explained here:
http://live.gnome.org/GnomeShell/Design

@James Cape We are holding off on fixing this bug because we’d like to focus on what is causing it, which is accommodating the legacy GtkStatusIcon(s) in the first place. We hope to have a lot fewer of them by the release of GNOME 3 and at least not have them for the core GNOME components and applications. I’m also going to try to make the accordion affect feel more stable soon by adding a timeout for the expansions and not collapsing the left-most item when you move past it to the left.

@jospoortvliet, @Aaron Seigo I see what the situation with the spec is. The changes, which are all optional extensions, were added as work-in-progress to accommodate the design of the message system in GNOME 3. As @ovitters says there is interest in the GNOME community to work on the common spec.

@ovitters Thanks for voicing the position of the release team in your comment.

@Dylan McCall The designs of the notification systems in Unity and GNOME 3 are tightly coupled with the desktop environments they are a part of, so they are not interchangeable.

It is a valid point that you need to mouse over to the notification or click on it in the message tray to get all of its content. The upside though is that the notifications are not intrusive, which was a major design goal.

Marina: Apologies for going somewhat offtopic on your blog.

Ubuntu is on to something with notify-osd. It makes sense in its own right, particularly with the added synchronous notifications for volume and brightness feedback. Perhaps the persistent stuff can be split from the transient stuff, called something different, and everything will be shiny and happy.
This happens with Toast Notifications vs. Status Bar Notifications in Android:
http://developer.android.com/guide/topics/ui/notifiers/index.html
You’ll find that same kind of design in many modern platforms.

With the implementation of this (so far) in Gnome Shell, I’m concerned that I need to click a notification — or at least scrub over it — to get any meaningful information beyond that a notification exists.

Android and WebOS both run on smartphones with 3-4 inch screens, and they make wonderful use of space. In Android, you almost always see an icon for every notification at the top left of the screen. You just need to swipe your finger once to see everything there is to know about every notification (including its description, progress bar, a nice picture, etc).

Now, on a 14-24 inch computer monitor, you need to first expose the message tray. Then you need to click each notification, one by one, to get the same kind of summary you get at a glance on a tiny phone.

Unfortunately, I can’t think of a particularly elegant solution that still uses the (quite awesome) message tray concept, but I’m sure there is one. Maybe each notification can be given some fixed horizontal space for dynamic information; something like the current window list (but prettier).

Good luck!