Identify rel=”nofollow” Links without Viewing the HTML Source Code

One of the most important skills an advanced SEO must possess is the ability to analyze and understand the link structure of a given web page or website. This skill can be applied to many different SEO-related topics, such as information architecture, link building, and the mysterious practice of PageRank sculpting. Even “content is king” advocates rely on links to deliver traffic, increase rankings, and to make their content discoverable to search engine crawlers.
Anyone who’s serious about SEO needs to be able to easily identify links that (a) cannot be crawled, or (b) cannot flow PageRank. Two common examples of this are:

• links that include the rel="nofollow" attribute
• links that are embedded in a page via inline frames (i.e. <iframe> elements)

In this article, I will show you how I have customized my web browser (Firefox 3.5) to help me identify nofollowed links and iframes, without viewing a page’s HTML source code. If you don’t use Firefox, you can still benefit from the CSS examples in this post, but you will have to figure out how to add custom user-defined CSS styles to your browser. If you’re using Internet Explorer, just kill yourself.