It's big news that Google now has a Disavow tool. However to understand why, we need to first take a quick look at the history behind it.
The history
Back in April (2012) Google released the Penguin algorithm update. This focused on trying to identify which sites were likely to be spam, or of low quality, by examining their backlinks.The result was that sites could now be damaged by low quality links. Webmasters quickly realized that by focusing large numbers of poor quality links at a competitor they could damage their rankings. This became known as ‘negative SEO’.
How effective negative SEO is has been controversial. Tests had an impact on some sites, while other sites have remained untouched. It is most likely that the number of poor quality links it takes to be damaging is directly linked to the strength of the sites’ backlink profile. Once sites gain a high enough level of authority it is likely that they can no longer be significantly affected by poor quality links.
Google is also getting better at assessing the proper value links. And as a result, webmasters have found that an increasing proportion of their backlinks are having a negative effect. Techniques such as placing links in directories used to improve your backlink profile. But now this technique, and others, are potentially damaging.
The Disavow tool
Webmasters have traditionally had pretty limited tools at their disposal for removing links. The only way to do it was to physically remove the link either by removing the page the link is on or breaking it by removing the page it's pointing to.Asking webmasters to remove links pointing to your site is known as a link removal request. These have had very mixed success and some webmasters have even started charging to remove links. Where larger numbers of links are causing problems it can be easier to just remove the page which they link to. This of course loses all the value from any good links which point to that page as well.
What was needed was a way to communicate with the search engines directly about links pointing to your site. This would allow webmasters to disassociate themselves from links which they felt were harmful. The search engines could then just discount these links from the site.
Bing saw that a way was needed for webmasters to communicate which links they didn’t want and in June released the Disavow links tool as part of its Webmaster tools suite. However Bing only holds a small share of the market (around 15%) against Google (67%) (US figures) meaning that it has been a long wait for Google to release its own Disavow tool.
How it works
The Disavow tools rely on the webmaster having a Google Webmaster Tools or Bing Webmaster Tools account and manually checking and requesting the removal of links. The exact process differs slightly in both tools.Google regard this as a safety net, to be used only once all other options have been exhausted:
“If you’ve done as much as you can to remove the problematic links, and there are still some links you just can’t seem to get down, that’s a good time to visit our new Disavow links page.”
Bing however see it as more of a catch-all and don’t emphasize trying more traditional routes first:
“Using the Disavow Links tool, you can easily and quickly alert Bing about links you don’t trust ...”
“These signals help us understand when you find links pointing to your content that you want to distance yourself from for any reason”
Google does allow you to upload URLs in bulk which could make it a significantly quicker process than Bing, depending on the level of accuracy you are looking for. Both will allow you to mark a URL as a domain to disavow all links from the site as a whole.
