Google uses numerous sources to find new webpages, from links we find on the web to submitted URLs. We aim to discover new pages quickly so that users can find new content in Google search results soon after they go live.
We recently launched a feature that uses RSS/Atom feeds for the discovery of new webpages.
RSS/Atom feeds have been very popular in recent years as a mechanism for content publication. They allow readers to check for new content from publishers. Using feeds for discovery allows us to get these new pages into our index more quickly than traditional crawling methods. We may use many potential sources to access updates from feeds including Reader, notification services, or direct crawls of feeds. Going forward, we might also explore mechanisms such as PubSubHubbub to identify updated items.