I'm not really sure I'm going anywhere with this, it was just a little thought that occurred to me. Maybe I'm misunderstanding web applications. I guess part of the idea with some of the widget standardization is that a widget written one place can be used in another place (like facebook versus igoogle (I don't know if that's currently how it works)). Is that some of the idea with opensocial?
Anyway... I guess the point is I've got lots to learn. Nothing new there.
[Update 8 May 2008: seems like this page is pretty relevant]