Another effect for social media sharing buttons is to put them in a cubic, which automatically gets opened when the mouse comes over it. The sense of 3D objects in two dimension page is always attractive and can gain more attentions and clicks!

HTML
<!-- this script got from www.devanswer.com -->
<div class="demo-container"> <div class="button"><i class="fa fa-share-alt"></i> <div class="fb soc-but"><a class="back" title="On Facebook" href="https://www.facebook.com/plugins/like.php?href=http://www.devanswer.com"><i class="fa fa-facebook"></i></a></div> <div class="tw soc-but"><a class="back" title="On Twitter" href="https://twitter.com/intent/tweet?text=DevAnswer&url=http://www.devanswer.com"><i class="fa fa-twitter"></i></a></div> <div class="pi soc-but"><a class="back" title="Pin It" href="https://www.pinterest.com/pin/create/button/?url=http://www.devanswer.com"><i class="fa fa-pinterest"></i></a></div> <div class="vk soc-but"><a class="back" title="On VK.com" href="https://vk.com/share.php?url=http://www.devanswer.com"><i class="fa fa-vk"></i></a></div> </div> </div> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css"><a style="font-size: 8pt; text-decoration: none" target="_blank" href="http://www.devanswer.com">Developer Code</a>
CSS
*, *:before, *:after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

.demo-container {
  width: 100vw;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background-image: radial-gradient(farthest-corner at 50%, white, #67989A);
}

.button, .soc-but {
  width: 7rem;
  height: 7rem;
}

.button {
  background: #042037;
  position: relative;
  -webkit-perspective: 300px;
          perspective: 300px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  color: white;
}
.button:hover .fb {
  -webkit-transform: rotateY(180deg);
          transform: rotateY(180deg);
}
.button:hover .tw {
  -webkit-transform: rotateY(-180deg);
          transform: rotateY(-180deg);
}
.button:hover .pi {
  -webkit-transform: rotateX(180deg);
          transform: rotateX(180deg);
}
.button:hover .vk {
  -webkit-transform: rotateX(-180deg);
          transform: rotateX(-180deg);
}

.soc-but {
  position: absolute;
  left: 0;
  top: 0;
  transition: -webkit-transform 0.4s ease;
  transition: transform 0.4s ease;
  transition: transform 0.4s ease, -webkit-transform 0.4s ease;
  -webkit-transform-style: preserve-3d;
          transform-style: preserve-3d;
}

.back {
  width: 100%;
  height: 100%;
  -webkit-backface-visibility: hidden;
          backface-visibility: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3.5rem;
  color: white;
  text-decoration: none;
}

.vk .back, .pi .back {
  -webkit-transform: rotateX(180deg);
          transform: rotateX(180deg);
}

.tw .back, .fb .back {
  -webkit-transform: rotateY(180deg);
          transform: rotateY(180deg);
}

.fb .back {
  background: #3b5998;
}

.vk .back {
  background: #45668e;
}

.tw .back {
  background: #00aced;
}

.pi .back {
  background: #dd4b39;
}

.fb, .vk {
  -webkit-transform-origin: 0% 0%;
          transform-origin: 0% 0%;
}

.pi, .tw {
  -webkit-transform-origin: 100% 100%;
          transform-origin: 100% 100%;
}

.tw {
  transition-delay: 0.1s;
  -webkit-transform: rotateY(-90deg);
          transform: rotateY(-90deg);
}

.pi {
  transition-delay: 0.2s;
  -webkit-transform: rotateX(90deg);
          transform: rotateX(90deg);
}

.vk {
  -webkit-transform: rotateX(-90deg);
          transform: rotateX(-90deg);
}

.fb {
  transition-delay: 0.3s;
  -webkit-transform: rotateY(90deg);
          transform: rotateY(90deg);
}