Android has an almost-identical "task switcher" (press and hold the Home button to show a popup of recent apps). I don't think anyone I know uses it regularly - and I just spent 18 months working in a 30-person Android software company.
As do I. It's one of the best things about Android, I've found. Going back and forth between two applications directly is very, very efficient for using a mobile OS, I've found. I think the author is wrong in saying that it appears as a "random selection" of apps. If I'm using it, it's because I remembered that I was just using another app. I'm not using it for discovery; I'm using it as a shortcut.
I use it all the time, too. It's essentially a taskbar for recently used or running apps. If I follow a link from Seesmic or Gmail, but want to keep the browser open, I <hold Home> and swap back to mail. Or maybe a song comes on that I don't feel like listening to at the moment, so I swap over and skip it in the same manner.
This is my primary way of switching between recent applications. Take it with a grain of salt, though, as the Android way of dealing with App icons is a world of a difference from iPhone.
Android uses a separate and almost useless alphabetically-sorted application's drawer. You are able to put applications on the home screens, but chances are that you are messing with an application that you don't use very frequently and thus have not placed it onto a home screen. In addition, on stock Android (not rooted/jailbroken), you only have 3 home screens.
Android OS 2.1 increases it to 5 homescreens. In addition, you can put folders on any of the Android homescreens that work almost identically (from what I gather from the description in the article) to the way folders work in iPhone OS4.
I think others have mentioned that you can get 3rd party apps for Android that increase the number of home screen to at least 7. These do not require rooting or anything else unusual, just a quick download from the Market.
WRT the 3 home screens, there are quite a few replacement Home apps that increase it to 7+ - PandaHome, aHome, and Open Home are the first that come to mind.
I can only speak for myself, but I definitely use task switching all the time. I spent a lot of time with a Nokia N810 http://en.wikipedia.org/wiki/Nokia_N810 before I had a smartphone, and its interface was more like a regular desktop, with a taskbar, etc.
Symbian has had essentially the same kind of task switcher for many years (hold the Home button to display a popup of open apps). AFAIK, nobody uses that either. It's not discoverable.
Sorry. I actually use the Symbian task switcher too. I should have said: "I suspect most users are completely oblivious to this method of switching between tasks". (The task switcher is also accessible from the main menu by pressing Option and choosing it from the popup menu, so that's probably how most people find it.)
