Marissa Mayer, in an early IO keynote, said she put the copyright note at the bottom, though arguably meaningless, to let people know the page was "done loading". She said that in initial user studies she did of the minimalist Google homepage (Sergey said it was that way because "I don't do HTML") people would just sit there doing nothing but watching the screen. When she asked what they were doing, they replied "I'm waiting for the rest of it". Websites loaded so slowly in '98, and ironically were also utterly covered in links and images and crap, that we were all accustomed to just sitting there until the pages fully appeared. So, while she didn't think the copyright necessarily meant anything from a legal perspective, it worked to tell people "there's nothing more to wait for, please proceed."