By definition, the link disavow tool is a Google Webmaster Central service, which allows webmasters to have Google check and as needed devalue unnatural or spammy links.
The fact that Google places a high value on relevant links and ignores dubious link sources, has become abundantly clear with algorithm changes of great magnitude such as the Penguin update. It resulted in many link sources being excluded from the index and the links of many websites were devalued. Google’s intention is to give webmasters the opportunity to report bad links to Google themselves with the link disavow tool.
In recent years the search engine Bing has provided a similar service for the devaluation of bad links. Google’s launch of such a service was therefore expected. Google launched the tool in October 2012.
The link disavow tool can be used once you are registered with a Google account and have a Webmaster Tools account set up. You first have to enter a domain that likely contains bad links. Later in the tool, a text file can be uploaded, which likely includes bad links. You have the option to place individual links in this text file or the links of an entire domain. With the upload function, the report can be sent directly to Google Webmaster Central. Google warns that this form should not be rashly submitted. The processing of the submission may take several weeks or months to complete.
After the launch of the link disavow tool, it was partly met with criticism. Similar to spam reports, the disavow tool has also been interpreted as “snitching.” In this case, webmasters should admit that they themselves have built up bad links. Google wanted to find out with this tool, which websites were affected. The assumption of the critics is that Google is unable to automatically filter out such sites that contain bad links. Some industry experts say that webmasters underestimate the use of the link disavow tool and could ultimately also harm themselves.