Fireriver is a project mainly written in JavaScript, it's free.
A magical River of News for Firefox
This is an experiment at building a magical River of news in Firefox.
It's probably not worth using right now; but it might look like this:
Fireriver will alert you whenever it notices a feed on any page you visit, and will offer the option to subscribe to that page or ignore it in the future.
Fireriver will create a new bookmark folder named "Fireriver Feeds"
Fireriver will use Live Bookmarks in this folder to build a River of News page. You can view it by clicking the blue feed icon in the add-on bar.
The space bar can be your main tool for paddling down the river.
You can add and remove Live Bookmarks in this folder like any other bookmark folder. The changes will be reflected in the river of news display.
If you organize your Live Bookmarks with folders, Fireriver will let you view items filtered by those folders.
If you leave the Fireriver page open, it will update itself whenever Live Bookmarks refresh with new items. (This may not always work, yet.)
If anything seems broken, try reloading the page. Someday, you shouldn't need to do this, ever.
Fireriver will try not to show you things you've seen before.
Everything Fireriver knows is tied to your Live Bookmarks. If you delete them, Fireriver's data goes away too.
Influenced by and thieving heavily from: