How Google's 'Disavow' Tool Can Help You Deal With Bad Backlinks But use with caution to avoid hurting rather than helping your search results.

Negative SEO and the potential impact of bad backlinks have been growing concerns for many webmasters since Google's Penguin update earlier this year, which sought to penalize low-quality backlinks. Indeed, because site owners often have no control over the external websites that link back to them, a competitor could intentionally point thousands of spam links at them to encourage penalties -- a practice that's known as "negative SEO."

But even sites that are not the target of these attacks can be penalized if the backlink building tactics they've used in the past no longer pass muster with Google's Webmaster Guidelines and they're unable to work with referring webmasters to have the low value links changed or taken down.

Fortunately, Google has finally offered webmasters an opportunity for redress through the new Disavow Links tool. Essentially, Disavow Links enables webmasters to submit files through the Google Webmaster Tools interface listing any links Google should devalue when determining the overall authority of the links pointing back at a website. If, for example, your website had five good links and one bad link pointing at it, a Disavow Links request would let Google know that you'd like only the five good links taken into consideration when your backlink profile is evaluated.

This sounds like a potentially great solution for webmasters who have struggled to remove low-quality backlinks from their profiles, whether in response to a "bad links" notice from Google, a rankings drop following an algorithm change or a suspected attack. But there are a few things to keep in mind regarding this new feature.

Related: 3 Post-Penguin SEO Tips for Backlink Cleanup

Disavow Links may do more harm than good: If your link request file is set up incorrectly or you've chosen to devalue links that aren't actually malicious, your site could inadvertently decline in the natural search results rankings. For example, if you choose to disavow links by domain rather than by individual bad backlinks in your request file, you risk eliminating potential benefits conveyed by any good links emanating from that website.

The tool should be used only in the event of a proven attack: Given the potential for unexpected harm to your rankings, most webmasters should use Disavow Links only when they're 100 percent sure that they've fallen victim to a negative SEO attack or when existing bad backlink issues can't be resolved by working with referring webmasters.

Diagnosing negative SEO attacks can be tricky, but you can start by determining whether any decrease in rankings or web traffic coincided with a known SEO algorithm change. For instance, if you saw a decrease in your website results around Oct. 5, 2012, when the Penguin 3.0 update rolled out, that was likely the reason for the drop, not an attack. (Here's a complete list of Google algorithm updates, from Seattle-based SEO and social monitoring service SEOMoz.)

Related: 3 Steps to Protecting Your Website's Search Rankings

Be aware that separating negative backlinks from benign or beneficial backlinks can be an arduous process. Not only will you need to pay for a service like Majestic SEO ($49.99 per month) to download your entire backlink profile, you'll need to ascertain which links are both malicious and actively causing harm. Even links that look dangerous may not be counted by the search engines, depending on how they are set up on the referring webmaster's site.

Disavow Links might not help your website results at all: Google has provided no concrete explanation for how it's using the data generated by the Disavow Links tool. While it may immediately disregard reported links from a website's backlink profile, the search giant has also reserved the right to carry out a manual review of all links submitted to decide which ones to devalue.

Certainly, submitting information to the Disavow Links tool can provide useful supporting evidence should your business ever need to request reconsideration following a penalty in search rankings. But given the potential for harm if the tool is used incorrectly, webmasters might want to consider seeking the support of a qualified SEO professional instead of attempting to diagnose and repair damage from SEO attacks on their own.

Related: 5 SEO Metrics You Don't Need to Obsess Over