In the image above, "Dataplan Monitor" is a widget. It is a small, running application that appears on the desktop. As I use my cellular data connection, Dataplan Monitor updates in real time to show current information. Tapping Dataplan Monitor launches nothing.

The three icons on the right side of the screenshot are shortcuts. They are simple, static images. Working from top to bottom, tapping them launches the Conversations, DialCentral, and Phone applications respectively.

The advantage of widgets is that they do things on the desktop. The advantage of shortcuts is that they launch applications. They're different beasts with different jobs.

You can place a mix of shortcuts, contacts, bookmarks, and widgets on each desktop screen as you like.

I expect people will write some innovative application launcher widgets & applications for Maemo 5. Personal Launcher was certainly popular on Maemo 4, and there's already work underway on a Gnome Do port to Fremantle. You'll likely have something that suits your needs soon, it's just not there out of the box.

I'm probably unusual, but I find I almost never see my desktop. I bounce between applications quite often, but that just has me playing with the application switcher. I haven't found much use for the desktop screens.