Edit in JSFiddle

body{
    background:#eee;
}

.box {
    width:300px;
    height:300px;
    position: relative;
    -webkit-box-shadow: 1px 2px 4px rgba(0,0,0,.5);
    -moz-box-shadow: 1px 2px 4px rgba(0,0,0,.5);
    box-shadow: 1px 2px 4px rgba(0,0,0,.5);
    padding: 10px;
    background: white;
    margin:40px;
}

.box:after {
    content: '';
    -webkit-box-shadow:  100px 0 10px 20px rgba(0,0,0,.2);
    -moz-box-shadow:  100px 0 10px 20px rgba(0,0,0,.2);
    box-shadow:  100px 0 10px 20px rgba(0,0,0,.2);
    position: absolute;
    width: 50%;
    height: 40px;
    bottom: 20px;
    right: 90px;
    z-index: -1;
    -webkit-transform: skew(-40deg);
    -moz-transform: skew(-40deg);
    -ms-transform: skew(-40deg);
    transform: skew(-40deg);		
}

<div class="box">
    影とか付けてみたりな
    <a href="http://net.tutsplus.com/tutorials/html-css-techniques/quick-tip-getting-clever-with-css3-shadows/">ちなみにこの方法はtuts+さんで知りました。</a>
</div>