First be sure you've got a fully updated river2.root. Bring the OPML app to the front, and choose river2.root from the Window menu. Then choose Update Front Tool from the Tools menu. You may find it already is fully updated.
Important: Be sure you've set your Twitter username in the OPML Editor preferences. You do not have to enter your password for this feature to work.
Go to your Home page. You should now see blue T's in the right margin. Pick a story you want to share. Click the blue T next to it. After a few seconds you should be on your Twitter page with the text of the Title and a shortened URL in the What Are You Doing? box, as shown below. If you want to tweet it, just click Update. That's all there is to it! :-)
It's taking a long time for the domain we'll use for this, r2.ly, to come through the registration process. So to begin with we'll use a teamrss.com domain to share links. If you see one of these on Twitter it's coming from this part of River2.
This feature is very much experimental, so please try to be thoughtful.
There may need to be some big changes as we learn how this works.
And share your thoughts in the comments below! :-)