One of the big components we need for the loosely-coupled 140-character network are user interfaces for browsing rivers.
That's the reason I published the JSONP version of my personal river, to help bootstrap the process by providing Javascript programmers a frequently updating stream of news to display.
If you're working on a display, please post a link in a comment and I'll add it to this post.
Right now I'm aware of:
Martin Duffy's river viewer, the first to appear on this page.
Ben Trask's entry in the River of News freestyle competition.
Here's another from crashbang.co.nz.
This is amazing: riverofnews.glowdart.com -- it's my personal river, flowing through the glowdart engine, thanks to JSONP.
Hopefully, more to come.