Google’s Additional Discovery Method: RSS and Atom Feeds

This is useful – from Search Engine Land:

For years, Google’s discovery of web pages was solely based on links. If a page had no links to it, Googlebot had no way of knowing about it and therefore, would never index it. Along the way, Google provided an option for submitting individual pages, but that wasn’t really a viable option for site owners [...]

See also Using RSS/Atom feeds to discover new URLs at Google Webmaster blog.