As blogging has risen in popularity, so has blog spam. Bloggers often load blog entries with links and comment spam. The goal, of course, is to link to other websites and pages to boost those external sites’ link juice and to boost search engine PageRank. In other words, the system of using hyperlinks to “vote” for the usefulness or relevancy of sites has been abused—often egregiously—by spammers hawking dubious wares and services.
Enter the “nofollow” tag, introduced by Google in 2005. The promise of the nofollow tag was not to stop spam (which itself is all but unstoppable), but rather to remove any of the link love value in a link in blog comments. The nofollow tag tells search engines that the link shouldn’t “count” as a vote of confidence in whatever page or site to which the link points. That’s why some SEOs refer to the nofollow tag as a “link condom”. Adding the nofollow tag to a hyperlink is supposed to effectively eradicate any value that link may confer on the page or site to which it points.
Nofollow is baked into the Google-owned Blogger platform by default, as well as most other blogging platforms, including the WordPress platform. (There are also workarounds for the technically inclined.) Numerous social bookmarking and photo-sharing websites also use nofollow tags for outgoing links. These include Digg.com, Furl, Propeller.com (formerly Netscape.com), Yahoo! My Web 2.0, YouTube, and Technorati Favs. Wikipedia also adopted the tag for its outbound links.
Because Google frowns on paid links, it also came up with another recommendation for using the nofollow tag. Google argued that site publishers who sell links solely for PageRank value were deliberately trying to stick it to the system. So, many publishers began to use nofollow tags to indicate to Google that they weren’t adding links or ads to their sites solely for the value of the link juice.
Some site owners even use nofollow tags internally. This directs search engine spiders not to follow internal links on their sites to pages such as the privacy policy, or “About Us” or “Contact Us” pages. The value of this practice is hotly debated. After all, there are searchers out there looking for precisely that information.
After Google introduced nofollow, Yahoo! and MSN said they would support the standard (although each search engine approaches nofollow differently), whereas Ask.com ignores it completely. Google claims not to follow links designated as nofollow at all, although this claim is disputed by many SEOs. However, Google does not index the linked-to page. Of course, it’s wholly possible that the page in question was already in Google’s index. Similarly, Yahoo! and MSN respect the attribute and exclude nofollow links from their ranking calculations.
Nofollow is an imperfect tool. There’s no across-the-board agreement on how to use it. Certainly it’s helped to stop the PageRank effect of some blog comment spam, but it’s not as if it’s stopped that particular genre of spam altogether (as any blogger sporting a comment feature will certainly affirm). Nofollow has also been criticized for discouraging comments from qualified professionals and opinion-leaders. Often, these qualified professionals don’t bother to add insightful feedback to blog entries because the link won’t pay off in link love. Google would like link sellers to use nofollow, but the practice is too widespread and non-transparent for any real kind of implementation in that regard.
So, use nofollow judiciously. One practical way it’s often implemented by site owners is in instances of linking to competitive sites, or information about competitors. Although the information linked to may be valuable or relevant to site visitors, at least you’re not helping boost the competition’s PageRank with the link.
Bottom line: The rel=“nofollow” attribute is here to stay; a few more years of testing and a few dozen search engine algorithms updates from now, it will likely have far different value than it holds today. Nofollow is an interesting tag that started on a simple-enough mission: to rid the world of spammers. It’s evolved into a tool to be used wisely and tested consistently.
Finally, bear in mind that nofollow does not render content invisible, preventing search engines from indexing it or users from finding it. If you have a need to block search engines from finding content on your own site, see Truth 51, “Sometimes you don’t want to be found,” in the final section of this book.