So what is a Parallax website you ask? Parallax websites are created in layers and when you scroll, the different layers move or scroll up and down at different speeds creating an illusion of depth. A website may have a background, overlay and content layer and you may have a big image sit in the background and the content layer could have the text. You could have something in the middle layer too. And now when the user scrolls up or down the background would move slowly compared to the text or the middle layer content, creating an illusion of depth. When you scroll up or down in a traditional website, all elements on the page move at the same speed.
Video games have been using the Parallax technique for quite some time now which involves different layers of images and graphics moving at different speeds causing this illusion of depth. This has recently been applied to the web world too giving a totally new dimension to websites using the Parallax effect. Web designers now have a new way of expressing their creativity and providing end users with a more enriching experience.
Have a look at the 23 Parallax scrolling websites listed below; the creativity and Parallax scrolling effects are mind blowing.