The blogging and podcasting phenomena are built on top of something called RSS, which stands for Really Simple Syndication. Essentially, RSS is a data format used to structure the content of a blog post or podcast so that any blog tool or podcast tool can work with it. The good news is that all of this is handled for you behind the scenes - every time you write a new blog post, you are publishing an RSS feed and every time you read a blog post in a newsreader you are consuming an RSS feed. The dominant version of RSS (RSS 2.0) has been in place for a couple of years and is used by millions of blogs and organizations throughout the world - it just works.
Behind the scenes, though, there is a continual battle to change, improve, or replace RSS. Many people want to modify the format to support additional features, but still call it RSS. This debate gets into some fairly technical issues, but here's the best summary available on why the RSS format should remain frozen:
RSS is by no means a perfect format, but it is very popular and widely supported. Having a settled spec is something RSS has needed for a long time. The purpose of this work is to help it become a unchanging thing, to foster growth in the market that is developing around it, and to clear the path for innovation in new syndication formats. Therefore, the RSS spec is, for all practical purposes, frozen at version 2.0.1. We anticipate possible 2.0.2 or 2.0.3 versions, etc. only for the purpose of clarifying the specification, not for adding new features to the format. Subsequent work should happen in modules, using namespaces, and in completely new syndication formats, with new names. [source]
Dave Winer, the man largely responsible for the format and its long-time advocate, has adopted this view and argued for it repeatedly publicly and privately. I'm on record as a Dave fan and I agree with him on this one. His efforts are motivated by a desire to do what's best for the users of RSS and the companies that have invested millions in the technology.
Here's another way to look at it. When Jerry Garcia passed away, the Grateful Dead had existed for 30 years. At that moment, the Grateful Dead ceased to exist. The rest of the band knew they would continue to perform, but they also knew that they would never perform under that name again. Over the next decade, the remaining members did shows as The Other Ones and later, The Dead. Whether better or worse, the new group was undeniably different than the original and they wanted to make sure it would never be confused with the Grateful Dead.
If you're building on top of RSS, create a new format and give it a new name. And if you want to work on RSS itself, involve Dave in the process. Unlike Jerry, Dave is (thankfully) still with us.