Easiest css for Facebook style "red" notifications

The best way to achieve this is by using absolute positioning:

/* Create the blue navigation bar */
.navbar {
  background-color: #3b5998;
  font-size: 22px;
  padding: 5px 10px;
}

/* Define what each icon button should look like */
.button {
  color: white;
  display: inline-block; /* Inline elements with width and height. TL;DR they make the icon buttons stack from left-to-right instead of top-to-bottom */
  position: relative; /* All 'absolute'ly positioned elements are relative to this one */
  padding: 2px 5px; /* Add some padding so it looks nice */
}

/* Make the badge float in the top right corner of the button */
.button__badge {
  background-color: #fa3e3e;
  border-radius: 2px;
  color: white;
 
  padding: 1px 3px;
  font-size: 10px;
  
  position: absolute; /* Position the badge within the relatively positioned button */
  top: 0;
  right: 0;
}

<!-- Font Awesome is a great free icon font. -->
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.3/css/font-awesome.min.css" rel="stylesheet"/>

<div class="navbar">
  <div class="button">
    <i class="fa fa-globe"></i>
    <span class="button__badge">2</span>
  </div>
  <div class="button">
    <i class="fa fa-comments"></i>
    <span class="button__badge">4</span>
  </div>
</div>

Here's one that includes animation for when the count changes.

http://jsfiddle.net/rahilsondhi/FdmHf/4/

<ul>
<li class="notification-container">
    <i class="icon-globe"></i>
    <span class="notification-counter">1</span>
</li>

    .notification-container {
    position: relative;
    width: 16px;
    height: 16px;
    top: 15px;
    left: 15px;

    i {
        color: #fff;
    }
}

.notification-counter {   
    position: absolute;
    top: -2px;
    left: 12px;

    background-color: rgba(212, 19, 13, 1);
    color: #fff;
    border-radius: 3px;
    padding: 1px 3px;
    font: 8px Verdana;
}




$counter
.css({opacity: 0})
.text(val)
.css({top: '-10px'})
.transition({top: '-2px', opacity: 1})

Animation with jQuery:

$('button').click(function()
{
    var $counter = $('.notification-counter')
    var val = parseInt $counter.text();
    val++;
    $counter.css({opacity: 0}).text(val).css({top:'-10px'}).animate({top: '-1px', opacity: 1}, 500);
});

It uses Font Awesome for the globe icon and jQuery Transit for the animation.

Probably absolute positioning:

<div id="globe" style="height: 30px; width: 30px; position: relative;">
 <img src="/globe.gif" />
 <div id="notification" style="position: absolute; top: 0; right;0;">1</div>
</div>

Something like that. Obviously you would want to change the specifics and probably use background images. The point is to emphasis the absolute positioning which it really consistent across browsers, at least in my experiences.