Google measures fresh content by the time stamp of the physical file found on a server. If you upload your website on November 15, 2010 then many of your pages will have that November 15 time stamp.
Time stamping on files is also how Google determines original ownership of intellectual property. If your time stamp is oldest then your images and articles will be considered the original source of that particular information.
There is a growing problem with this time stamp concept when using content management systems. In a Google training video in 2010, someone asked what Google was doing about management systems that create a static page, but populate it with new information daily.
When Google checks the time stamp on a web page, it ignores the page if the time stamp is still the same as its last visit. In other wo...