If you’re interested in learning more about how Google retrieves and displays RSS/ATOM feeds that end up on personalized homepages, the folks in Mountain View have just posted an FAQ about what they call Google “FeedFetcher.”
Feedfetcher is how Google grabs RSS or Atom feeds when users choose to add them to their Google homepage. Feedfetcher collects and periodically refreshes these user-initiated feeds, but does not index them in Google’s search services (feeds only appear in our search results if they’ve been crawled by Googlebot).