One among the various weaknesses of Google Reader was that the feeds weren't updated very frequently. In fact, Google checked to see if there's any new item in a feed every 3 hours if a had a single subscriber, and every hour (or more often) for the rest of the feeds.
A more efficient way to update feeds is to use a ping mechanism. A lot of blog authoring tools send pings to specialized services every time someone creates a new post. Google Blog Search has a ping service, "a way to inform Google Blog Search of weblog updates. These updates are then published and shared with other search engines to allow them to discover the changes to your weblogs. In addition, Google Blog Search will add submitted weblogs to the list of blogs it needs to crawl and index."
I noticed that Google Reader's last update time is identical to the one from Blog Search. Apparently, Google Reader started to use the pings from Blog Search, so the updates will be much faster and you'll actually get the latest news right after they are posted.
Feeds, Google Reader, Feed Aggregator, Google