From Inside Search : The Official Google Search Blog
Search results, like warm cookies right out of the oven or cool refreshing fruit on a hot summer’s day, are best when they’re fresh. Even if you don’t specify it in your search, you probably want search results that are relevant and recent.
So now you know that a neglected website will loose search rank. This is important because Google seldom reveals how they evaluate websites for search rank. There are many similar SEO techniques that are similarly difficult to prove except by carefully documenting changes and measuring results. I wrote an article about blogging for top search rank if you are the DIY-SEO type. Otherwise…