Creating Multi-Document Workspaces

You can't always expect to sit down in a series of sessions and then produce an idea, all kind of in the forefront of your mind. Without the expectation that you're going to be explicitly building up your new idea, it's really easy for tools to accidentally build walls for thatt. One very interesting design decision is that, by default, documents are kind of a work space. But if you're working on several interesting questions and ideas at once, it's not at all clear that you'll have interactions between those work spaces that are necessary.