[SpicyLemonZest]

Like the Facebook timeline (and I don't think that's a coincidence!), newness is a big factor but not the only factor. They publish their "top stories" section as an RSS feed (http://rss.cnn.com/rss/cnn_topstories.rss), and you can see it's both not strictly chronological and clearly has editorial topic selection, as opposed to their "most recent" feed (http://rss.cnn.com/rss/cnn_latest.rss) which seems to be a true chronological order of everything they publish.