A thought on iPhone/iPad multitasking

I was playing with the This American Life iPhone app. I noticed when I clicked on the YouTube video placeholder, rather than quit the app, it used a modal view to display the video. This may be a built in feature of the UIWebView. I haven’t really messed with the UIWebView so I’m not entirely sure. My point is Apple provides that sort of thing along with the MailComposer view.

I wonder if a replacement for some multitasking actions would be allowing a developer to create view controllers that could be used by other applications. Similar to the URL API the iPhone already supports, but without having to leave the original app you were in.