Jeff Nolan wrote an interesting article title "Is Twitter Killing RSS?" I want to respond and decided to respond here on The RSS Weblog, rather than in Jeff's comments, as I'd like everybody to read this follow-up.
RSS is a protocol and Twitter is an application. Many publishers are using RSS-to-Twitter gateways to update their Twitter account when new items are publiched on their blog. The protocol and application are not competitive at all. In fact, they are complimentary. Twitter is not an RSS-killer, but rather a use-case for RSS.
Further, Twitter not only can import RSS, but it exposes an RSS feed so that you can inject your Twitter data into other applications. Many social websites are trying to import your Twitter updates. That RSS feed is likely the easiest way to do exactly that. Hmmm! Must play.
Last, could Twitter replace RSS for audience acquisition (as Jeff suggests)? Of course it could for some publishers, but it'd be a bad idea. Remember that Twitter is mostly used by us geeks. Most people are not trying to target geeks, but rather are targeting people like my wife, kids, parents, brothers and sisters. Not one of them have any clue what Twitter is and obviously don't use it. On the other hand, many of them are using RSS even though they really don't know what RSS is. That's because RSS is a protocol (under the hood). Twitter is just an application. Someday, the geeks will get bored with Twitter and move on. RSS is a protocol of the Web and it's not going anywhere.