Note: when the year changes from 2004 to 2005 your copyright notice should not change from 2004 to 2005. It should change to 2004-2005. Otherwise you are telling the world that you make no copyright claims in previous years. Thus, in the worst case scenario, someone could claim they invented your idea first because clearly you didn’t invent it until 2005.

Copyright notices are not trivial little bits of text. They are a legal reservation of intellectual property rights. They are important and the dates should represent the dates of creation of every aspect of your web presence. Most sites that say © 2005 should probably say © 2000-2005 or something like that.