According to Cutts, the freshness of the content on your site is considered to be a ranking factor for the search engine but this is only one of as many as 200 ranking factors that the search engine consider when looking at a site, meaning that if you are focused within a niche area that has plenty to cover, then you need to be looking to update the site as much as possible, something that Google relate to the fact that the site would be more use to search engine users.
Within the video, Cutts is asked "Google has expressed in the past that frequently updated pages get a boost in rankings (QDF), that seems to favour blogs and news sites over company sites, which have less reason to be updated often. How important of a signal is ‘freshness'?".
In his reply to the question, Cutts pointed out that so called ‘freshness' is not something that can be directly linked to improved rankings however making sure that your site has freshness where possible, your site would be meeting one of the signals that Google use in order to rank a site, however he did also point out that this is something that doesn't affect everyone.
According to Matt, niches such as news sites and sites within areas that offer plenty of new information should be looking to keep their content fresh as this would improve the experience that the user would have on your site, so the comments seem to be aimed more at time specific content rather than the sort of information that Cutts refers to as "being able to stand the test of time".
Although as a website owner you will be wanting to trigger every ranking factor possible when it comes to trying to increase the search engine rankings of your site, Cutts pointed out that if your niche doesn't have frequent call for update, don't force changes in order to mimic the addition of new content, such as editing the working of existing content and the date on which it was placed onto your site as this is not the sort of ‘freshness' that they are looking for.
Finally Cutts pointed out that website owners should be looking to create content that would be able to "stand the test of time", seemingly showing that Google are looking for more authority content to be created, which isn't new insight, but it does show that quality content that will be able to become a resource will always be held in high regard by the search engine giants.
You can see the latest Google Webmaster Tools video which shows Matt answering the question below: