“Sunlight is said to be the best of disinfectants; electric light the most efficient policeman.” Louis Brandeis (Other People's Money: and How the Bankers Use It, 1914)

Linking directly to Internet misinformation and explaining why it is wrong is skepticism’s answer to Brandeis’ sunlight. But because Google and the other search engines use hyperlinks to determine the importance of web pages, many skeptics are fearful of linking to pseudoscience and paranormal sites. They fear that doing so will help (in some small way) boost the visibility of misinformation on the Internet.

They are right. Every time we link to the sites of our cultural competitors, we give them a tiny boost up in the search engines. It’s as if we’ve contributed ten cents to a fund for them to eventually buy a billboard. Those coins eventually add up.

I’ve seen some skeptics try to deal with this in various tricky ways. Some don’t link at all or include the URLs as unlinked plain text. (This inconveniences and annoys your readers). Some link through a link shortening service like TinyURL. (This does not work - Google still counts the link).

Some have even gone so far as to create a special online service to solve this problem. One which targeted British tabloid newspapers had the unusual name of IstyOsty. It looked and acted like a URL shortener but it was actually what technicians call a “proxy service”. That kept Google from following the link, but it also violated copyright laws. As a result, IstyOsty was forced out of existence back in August.

There is a simpler way to deal with this issue (which I wrote of three years ago on my blog) called NOFOLLOW.  Read my original post for all the gory technical details, but essentially you add a special tag to each hyperlink to tell Google and other search engines to ignore that link for purposes of ranking content. A normal hyperlink looks like this when you create a web page:

<a href=”http://bad.example.com”>This is a link</a>

And a “nofollow” hyperlink looks like this:

<a href=”http://bad.example.com” rel=”nofollow”>This is a link</a>

It’s as simple as that.  I recommend that skeptical bloggers and webmasters make sure to always nofollow links to sites which we are debunking.  It should be our standard practice.

Some time after my original post, a handful of skeptics expressed doubts about my recommendation. You can see some of their objections in a thread in the JREF Forum.  I won’t reiterate all of the arguments here, but let me address a few of them.

For those who saw a fairness or reciprocity issue, I would point out that most of our cultural competitors do not even bother to link back to our sites. They act as if we don’t exist. So the argument that we shouldn't do it to them because they don’t do it to us, is (more often than not) moot.

For those who argue that nofollow is intended as an anti-spam measure, and my suggestion is a misuse of it, I would point out that Google’s own documentation contradicts that.  Quoting from their SEO Starter Guide, page 23:

Another use of nofollow is when you're writing content and wish to reference a website, but don't want to pass your reputation on to it. For example, imagine that you're writing a blog post on the topic of comment spamming and you want to call out a site that recently comment spammed your blog. You want to warn others of the site, so you include the link to it in your content; however, you certainly don't want to give the site some of your reputation from your link.

I think this clearly describes skeptical blogging.

Finally, for those who saw this as a way to cheat other website owners out of rightfully gained clicks or traffic: you’re wrong. A nofollow link is still a working hyperlink. If you click it, the other site gets a traffic hit like normal. It gets to display ads just like normal. They are not denied readers or the opportunity to make their case.

Criticism notwithstanding, I was pleased to see that many skeptics agreed with my recommendation back in 2008.  In fact, some have adopted it as a standard practice and evangelized it to other skeptics as well.

Australian skeptic Joel Birch decided to take it one step further. Knowing that the extra tagging could sometimes be tedious, he built a tool to automate it called NoFollowr. This is a plug-in for the WordPress blog software that makes adding the necessary tag as simple as a single click. I recommend it if you run a site on WordPress.

Since then, a further reason to use this technique has emerged. Although the quality of inbound links to your site are a primary driver in your Google rank, it is also true that outbound hyperlinks can affect your ranking.  In a YouTube video entitled “Can my blogroll affect my blog's reputation in Google?”, Google employee Matt Cutts warns not to link out to "spammy sites".  

I'm not saying that pseudoscientists are necessarily spammers, but do you trust them not to be? I don’t. I recently documented on my blog how some chiropractors deeply misunderstand how Google ranking works.  If we’re not careful with our links, their lack of knowledge could actually damage our efforts.

A casual survey of top skeptic sites reveals that we still have a long way to go.  Several major skeptical bloggers still do not make a habit of using nofollow. (You can check this yourself by choosing the “view source” or “view page source” option in your browser and looking for the nofollow tag).  Especially if the site is highly prominent, these links are subtly undermining our efforts to improve the overally accuracy of science information on the internet.

I hope that by calling attention to this technique again here, I can make it standard practice for skeptical blogs. If you blog, make it your habit. And use the “view source” trick check to see that your favorite skeptical writers have made it their habit too.

Tim Farley is a JREF Research Fellow in electronic media. He is the creator of the website What's the Harm and also blogs at Skeptical Software Tools. He researched the information in JREF's Today in Skeptic History iPhone app and has given presentations at TAM 6, 7 and 9. You can follow him on Twitter here.