You've got two RSS feeds for your site:
First is the main feed. There is a link to it on the top of your sidebar. All your posts will show up in this RSS feed. If you want to keep posts out of the feed (for example, you've made a minor spelling fix and don't want to prod your readers) just leave the News field of a post blank.
The second feed helps you stay on top of your site. It is the comments feed. Find it under your Admin page. The most recent comments will appear there, and comments will be removed from the feed once you re-edit and incorporate them.
A series of rapid edits (each less than ten minutes apart) will only generate a single entry in the RSS feed.