I need an outliner to manage my email drafts. In a perfect world I'd be able to plug one in. But we are very far from that. We were closer in the late 80s and early 90s. That was my goal then, to turn the apps of a GUI into toolkits for people who wrote scripts to connected them to create their own applications. Why should I have to write a whole word processor to have a new feature that no one else knows they need. If I could hook my emailer up to my outliner, I would get better use of the drafts I wrote. The ultimate goal is to do all my writing in my favorite writing app, and send pointers to the writing to the other apps, emailers, chat apps, CMSes, there would be only one original, and if I made a change to the original the updates would flow to all the places I sent pointers. Again we were much closer to this 30 years ago than we are now. But I think we have a chance to start fresh now with these goals. That's when you want to do this kind of integration for interop, at the beginning, before there are any apps. It's very hard to retrofit later, I can't say I've ever seen it work.