How to start your own discussions...

1. Drag the twdsc.us bookmarklet into your browser's toolbar.

2. If you see a tweet you want to discuss, open it in its own page, then click on the bookmarklet.

3. twitter.com opens with the edit box filled in with a pointer to the discussion page.

If you have questions, I've written a blog post that explains and provides a place to comment on the service.