Description:
Hiding spammy content (links, spammy texts, etc) on legitimate web pages is a common black hat SEO trick. It helps use existing site pages in black hat SEO schemes while keeping it invisible to site visitors and webmaster.
There are many techniques that help hide certain parts of a web pages. Most of them include either CSS or JavaScript. The simples is placing spammy content inside a div tag with the display:none; style.
There are many more variations of using various tag styles to hide them. Here are just a few of them:
<div style="position:absolute; left:-200%; top:-200%;cursor:default;" id="fb-friends-list">
...
<div style="position: absolute; overflow: hidden; width: 2px; height: 1px; left: -288; top: -277; z-index: 177;">
...
<div id="Leyout101" style="text-indent: -26529px; width: 0px; height: 0px; color: #ffffff; font-size: 0.1px; display: no
ne;">
...
<style>.dbhcc { dispLAy : NOnE } </style>
<div class=dbhcc>
...
<div style="position: absolute; top:-20px; width:100%; height:20px; text-align:center;">
...
<h2 style="overflow: auto; position: fixed; height: 0pt; width: 0pt;">
...
<div style="transform:translateX(-2047px);">
...
<p style="color:transparent;">
...
<div style="position: absolute; filter: alpha(opacity=0); opacity: 0.001; z-index: 10;">
JavaScript can also be used to manipulate with tag styles and their visibility
<script type="text/javascript">document .write("<div style='height:1px; width:1px; overflow:hidden'>");</script>
Affecting: Any web site (no specific target).