Google reader is an amazing web-based feed reading application. One of it’s most outstanding features is the ability to archive feeds, and show you posts from the feed regardless of when you subscribe. You see, normally, RSS and ATOM feeds only contain the 10-30 of the most recently posted items, but since Google Reader stores all the posts from the subscribed feeds, they’re (usually) all available if you keep scrolling down in the interface.
This makes it an awesome feed caching and archival tool. However, not many people are aware that you can actually extract the data back out, in one mega standard ATOM file.
Just enter this URL in the address bar:
…where FEED_URL is the address of the feed and NUMBER_OF_ITEMS the number of posts to extract.
For example, http://www.google.com/reader/atom/feed/http://feeds.feedburner.com/blogspot/MKuf?r=n&n=100 should return the latest 100 posts from the Official Google Blog as an ATOM/XML file.