“nofollow” is an attribute that can be added to a link that tells search engines not to follow that link. This is useful because it allows the control of link authority as it naturally flows through a Web site, thereby increasing the value of important site pages, which can result in improved visibility in search results for those pages.

For example, many pages that are typically contained in global navigation (linked from every page of a Web site) may not send users to a conversion, so limiting the value passed to these pages could have a large impact on the overall performance in search results.

According to Google: Here are some cases in which you might want to consider using nofollow:

·         Untrusted Content – typically used for user generated content like comments

·         Paid links – if you are selling links to other Web sites for promotional purposes

·         Crawl Prioritization – directing the path and priority for search engine crawlers

Proper use of “nofollow” allows Web publishers the ability to control the priority of the pages a search engine crawls, the internal links they crawl, and the value that is passed to each page.

Google has noted that they have limited resources when crawling Web sites, so they set priorities based upon their own internal process. However, effectively implementing an optimized robots.txt, XML sitemap and a “nofollow” strategy will help set priorities and funnel the strength of your site to key pages.