RSS and Data Signaling

One of the newer trends coming out of the rss community is integrating the technology on the application end with the purpose of signaling the application of new data.  Two areas this is currently being employed on are in appcasting and in torrentcasting.  In appcasting, you're able to notify the user of application updates using a simple rss form - and since theres boilerplate code for the application-end code, this makes it really easy for a developer to incorporate.  Torrentcasting is employed oftentimes on series-related distributed over the bittorrent network, and allows for notifying and downloading everytime a new "element" of the series is added (A new episode of a TV show comes out, and your bittorrent client automatically picks it up).  The two technologies, which are centered around the RSS 2.0 spec, ads an interesting extension in the field of web 2.0 enabled web applications - A bittorrent tracker can more acutely feed its way into the desktop experience of a user with torrentcasting.