I thought this post on Hacker News that I didn’t actually read yet had a really nice fade-effect on the bottom as you scroll. Turns out it is pretty easy to implement on browsers that support css gradients.

#content-bottom-fadeout {
    position: fixed;
    bottom: 0px;
    width: 100%;
    height: 30px;
    background: linear-gradient(rgba(255, 255, 255, 0) 0px, rgba(255, 255, 255, 0.75) 50%, #FFF 100%) repeat scroll 0% 0% transparent;
}