Maps the Radio2 style RT standard onto the Press This URL. (see A standard for RT'ing?)
This plugin checks for any of three query string params (link, title, description). If they are present it redirects the page to the /wp-admin/press-this.php page with the params u, t, s and v set appropriately.
The purpose is so static rivers like http://tech.newsriver.org/ will be able to send a RT request to your blog.
UPDATE: I haven't abandoned the plugin yet, but I'm thinking perhaps I should. It seems that Dave has moved on from promoting the standard and is not supporting it in Fargo or in any of his currently published rivers.