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).

机器翻译上文如下：

垃圾邮件-seo.hidden_content

描述：
在合法网页上隐藏垃圾内容（链接、垃圾文本等）是一种常见的黑帽 SEO 技巧。它有助于在黑帽 SEO 方案中使用现有网站页面，同时使其对网站访问者和网站管理员不可见。

有许多技术可以帮助隐藏网页的某些部分。其中大多数包括 CSS 或 JavaScript。简单的方法是将垃圾内容放置在带有 display:none; 风格。

还有更多使用各种标签样式来隐藏它们的变体。这里只是其中的几个：

<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 { 显示：无 } </style>
 <div 类=dbhcc>
 ...
 <div style="position: absolute; top:-20px; width:100%; height:20px; text-align:center;">
 ...
 <h2 style="溢出：自动；位置：固定；高度：0pt；宽度：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 也可用于处理标签样式及其可见性

<script type="text/javascript">document .write("<div style='height:1px; width:1px; overflow:hidden'>");</script>

影响： 任何网站（无特定目标）。