My experience is oddly the opposite: I am constantly setting Google to search only the last year because I keep getting irrelevant results from 2002. This is because the things I am searching for are often truly obscure. Tim Bray notwithstanding, Lou Reed’s Rock n Roll Animal album is not obscure. But the main point here is that Google "cares about giving you great answers to the questions that matter to you right now." It keeps track of things like how popular a page is. Bray says Google "it needs to be indexed, just like a library." It does not.