How can we create the vertical bar / spiral / splash kind of page animation effect found as we scroll down the web page at http://grouek.com/ website? I guess it is CSS3 or something advanced than it like Canvas. But is there any way to do it in CSS3 or jQuery?
yea, to have such stunning effect we have to invest some efforts or money to get it. But since you tried to search but no hint, i will show you some starters :)
http://janpaepke.github.io/ScrollMagic/
http://johnpolacek.github.io/superscrollorama/
http://prinzhorn.github.io/skrollr/
there are a lot more libraries available out there, but it is alwasy fun to create ourselve ;P