Placement of a status area

I have read with great interest this discussion relative to web applications.

Now I'm facing a very similar problem with respect to notification/status information inside Desktop applications. There are some design guidelines from Microsoft here describes the role of notifications, giving clear distinction wheter to use a "growl" (notification are baloon) or a status bar, but they do not explain why they are built the way they are and positioned where they are (bottom).

I guess one answer is "tradition": it is a common element of the classic Windows UI.

On the other end, web applications always display "status" and notifications at the top: this site, twitter/facebook, ... Google documents display some status information, things yuo find in the status bar usually, in the empty space at the right of the menu bar.

And even in Windows recently I have seen something different from Visual Studio with Notifications

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The notification icon is inside the title bar, at the top.

Why status in desktop is at the bottom, in web at the top?

The only answer I found, but I have no idea if it is supported by studies/facts, is that this might be due to the fact that the web is "bottom - less": a web app/page very often has a top, but a very "vague" bottom. Is a scrolling page more than a square window. So: no bottom - no status bar at the bootom.

Is this a valid reason? Are there any other, more compelling?

In general, it is better for a desktop application to put status and notifications on top (in the title bar, in an ad-hoc space, ...), or at the bottom (in the classic status bar)? Where would be more noticeable?