Google observes how frequently a page updates, and refreshes frequently-updated pages more often than rarely-updated ones. I believe it also ranks new content h

Google observes how frequently a page updates, and refreshes frequently-updated pages more often than rarely-updated ones. I believe it also ranks new content higher than old content, all else equal, presumably to allow recent coverage of current events to show up even though it won't have many links to it (and thus low pagerank).