What part of my comment made it seem like I need to be educated about what RSS is? I think it would have felt nicer for you to inquire rather than just tell me what RSS is.
I’m saying that it’s easily possible to imagine a world where the uses of RSS vary from what they’re used for today — different from the parent commentor.
Your comment didn't educate HN readers sufficiently; I thought it could use a technical backgrounder which could help others imagine the use cases and trade-offs. (I don't understand the Twitter architecture enough to add that for comparison, but perhaps many readers are more familiar with Twitter than RSS due to its popularity.)
It's like a web page, itemized into a very regular syntax.
If you want to "tweet" using RSS, you need a URL somewhere where you can upload updates to XML content; then give people that URL.
Either you have to join some website where content (like blogs) you create are exported as RSS feeds, or else run your own domain.