Taking a clue from Bing Webmaster's Disavow link feature that was introduced this year in June, Google today added a new tool to Webmaster Tools enabling users to disavow links to their site.
"If you've been been caught up in linkspam and notified of a manual spam action based on "unnatural links" pointing to your site, this tool can help you address the issue," Matt Cutts posted in the blog entry annoucing the feature. If you get this message, Google recommend that you remove from the web as many spammy or low-quality links to your site as possible as it addresses the problem at the root.
Adding, "We send you this message when we see evidence of paid links, link exchanges, or other link schemes that violate our quality guidelines," he said.
Further he writes, "Links are one of the most well-known signals we use to order search results. By looking at the links between pages, we can get a sense of which pages are reputable and important, and thus more likely to be relevant to our users. This is the basis of PageRank, which is one of more than 200 signals we rely on to determine rankings. Since PageRank is so well-known, it's also a target for spammers, and we fight linkspam constantly with algorithms and by taking manual action."
If despite all your efforts, you're unable to remove the problematic links, that's where "Disavow links" comes to your rescue. "When you arrive, you'll first select your site. You'll then be prompted to upload a file containing the links you want to disavow. The format is straightforward. All you need is a plain text file with one URL per line," Google explains.
Below is an example of a valid file might look like:
Cutts explains, "to find bad links, visit the "Links to Your Site" feature in Webmaster Tools. From the homepage, select the site you want, navigate to Traffic > Links to Your Site > Who links the most > More, then click one of the download buttons."
"This file lists pages that link to your site. If you click "Download latest links," you'll see dates as well. This can be a great place to start your investigation, but be sure you don't upload the entire list of links to your site -- you don't want to disavow all your links!"
To learn more about the feature, watch the video below, Cutts explaing Disavow links, and check out this Help Center.
Update: Here is the Google's Q&A from Google's blog post:
Q: If I disavow links, what exactly does that do? Does Google definitely ignore them?
A: This tool allows you to indicate to Google which links you would like to disavow, and Google will typically ignore those links. Much like with rel="canonical", this is a strong suggestion rather than a directive--Google reserves the right to trust our own judgment for corner cases, for example--but we will typically use that indication from you when we assess links.
Q: How soon after I upload a file will the links be ignored?
A: We need to recrawl and reindex the URLs you disavowed before your disavowals go into effect, which can take multiple weeks.
Q: Can this tool be used if I'm worried about "negative SEO"?
A: The primary purpose of this tool is to help clean up if you've hired a bad SEO or made mistakes in your own link-building. If you know of bad link-building done on your behalf (e.g., paid posts or paid links that pass PageRank), we recommend that you contact the sites that link to you and try to get links taken off the public web first. You're also helping to protect your site's image, since people will no longer find spammy links and jump to conclusions about your website or business. If, despite your best efforts, you're unable to get a few backlinks taken down, that's a good time to use the Disavow Links tool.
In general, Google works hard to prevent other webmasters from being able to harm your ranking. However, if you're worried that some backlinks might be affecting your site's reputation, you can use the Disavow Links tool to indicate to Google that those links should be ignored. Again, we build our algorithms with an eye to preventing negative SEO, so the vast majority of webmasters don't need to worry about negative SEO at all.
Q: I didn't create many of the links I'm seeing. Do I still have to do the work to clean up these links?
A: Typically not. Google normally gives links appropriate weight, and under normal circumstances you don't need to give Google any additional information about your links. A typical use case for this tool is if you've done link building that violates our quality guidelines, Google has sent you a warning about unnatural links, and despite your best efforts there are some links that you still can't get taken down.
Q: I uploaded some good links. How can I undo uploading links by mistake?
A: To modify which links you would like to ignore, download the current file of disavowed links, change it to include only links you would like to ignore, and then re-upload the file. Please allow time for the new file to propagate through our crawling/indexing system, which can take several weeks.
Q: Should I create a links file as a preventative measure even if I haven't gotten a notification about unnatural links to my site?
A: If your site was affected by the Penguin algorithm update and you believe it might be because you built spammy or low-quality links to your site, you may want to look at your site's backlinks and disavow links that are the result of link schemes that violate Google's guidelines.
Q: If I upload a file, do I still need to file a reconsideration request?
A: Yes, if you've received notice that you have a manual action on your site. The purpose of the Disavow Links tool is to tell Google which links you would like ignored. If you've received a message about a manual action on your site, you should clean things up as much as you can (which includes taking down any spammy links you have built on the web). Once you've gotten as many spammy links taken down from the web as possible, you can use the Disavow Links tool to indicate to Google which leftover links you weren't able to take down. Wait for some time to let the disavowed links make their way into our system. Finally, submit a reconsideration request so the manual webspam team can check whether your site is now within Google's quality guidelines, and if so, remove any manual actions from your site.
Q: Do I need to disavow links from example.com and example.co.uk if they're the same company?
A: Yes. If you want to disavow links from multiple domains, you'll need to add an entry for each domain.
Q: What about www.example.com vs. example.com (without the "www")?
A: Technically these are different URLs. The disavow links feature tries to be granular. If content that you want to disavow occurs on multiple URLs on a site, you should disavow each URL that has the link that you want to disavow. You can always disavow an entire domain, of course.
Q: Can I disavow something.example.com to ignore only links from that subdomain?
A: For the most part, yes. For most well-known freehosts (e.g. wordpress.com, blogspot.com, tumblr.com, and many others), disavowing "domain:something.example.com" will disavow links only from that subdomain. If a freehost is very new or rare, we may interpret this as a request to disavow all links from the entire domain. But if you list a subdomain, most of the time we will be able to ignore links only from that subdomain.