Search engine optimization is characteristically veiled in a shroud of imprecise speculations and anecdotal evidence. While there are some hard, objective factors that can help a site rank higher, the remainder of our collective knowledge on SEO is, at times, unhelpful due to the unpredictable nature of the digital world.
Google is constantly changing its standards for what makes a site “authoritative,” and which ranking signals are most important, but there are some tenets that have been consistent, such as high quality content and reputable, natural backlinks. So what happens when one of these ranking signals, such as a backlink pointing to your site, disappears?
The Relationship Between Backlinks and Site Rankings
First, let’s take a look at the relationship between backlinks and site rankings. In the old days of SEO, search marketers would litter the web with backlinks, knowing their association with higher page rank. Fortunately for web users, Google has released a series of updates, including Google Penguin, which eliminated spam-like backlink practices in favor of a more natural system of authority measurement.
What does that mean for modern link builders? Well, like we mentioned, there’s a bit of a veil blocking us from understanding exactly what makes a link significant in the eyes of Google. We know that Google can tell when a link is relevant (such as determining whether the location of the link is related to the host site’s industry), and keeps count to detect when a site is engaging in spam. But we also know that adding more high-quality links (and their new cousin, brand mentions) generally results in higher page rank over time.
The Concept of “Link Echoes”
Clearly, the number of links you have pointing back to your site is important, to some degree. Adding links can improve your page rank, but what happens when you take a link away?
Logically, because there is some dependency on the sheer number of links available, taking away a given link should result in a decreased rank. However, search marketerslikeMoz founder Rand Fishkin have noticed a strange and intriguing pattern; when a backlink is removed from an external site, in some cases, the site’s rank will not drop. And in some cases, the site’s rank will actually increase.
This phenomenon has been observed and debated for several months, sometimes called the result of “link echoes” or “link ghosts.” When the team over at Moz ran a formal experiment, they took two similar sites and for each of them, built 22 links using 22 identical sources. Naturally, the link increase resulted in a measurable rise in ranks (the exact rise was different for each site, due to differences in anchor text). After this phase of the experiment, the researchers then removed all 22 links from both sites, expecting their ranks to drop back down. However, both sites stayed exactly where they were.
Moz repeated this experiment multiple times, and under each condition, the sites stayed at the same rank or only dropped one or two positions. There were no major external factors that could have affected this experiment, suggesting that the concept of a “link echo” is real. The authority you get from a backlink can continue supporting your site even after the link is taken down.
Why is this phenomenon occurring?Of course, Google wisely keeps most of its secrets under lock-and-key, but there are several theories that plausibly explain the mechanisms behind this effect.
Theory One: Reverberation of Link Power
The first theory is the most straightforward, though it doesn’t explain the mechanics behind the effect. It could be that Google’s algorithm is built specifically to “remember” links that once existed, or catalog them as a factor in a site’s ranking. This would lead to a reverberating effect, theoretically giving preference to links that still exist but also taking former links into consideration. It is unclear how long this reverberation period lasts, though experiments suggest it lasts at least a few weeks. If this theory is true, the reverberation period likely varies depending on the type of site and the type of links used to support it.
Theory Two: Improved Site Performance
It’s also possible that there is nothing in Google’s algorithm that specifically produces the link echoing effect. Instead, the external links could naturally produce more traffic to the site in question, which would then be viewed and analyzed as an indication of higher site relevance by search engines. Even when the link disappears, that effect of that increased site performance could remain. If this is the case, then external links aren’t as relevant to the ranking process as the secondary effects generated by those links. It’s tough to put this theory to the test since it relies on specifics within algorithm data unavailable to the public.
Theory Three: Other Factors
Of course, both of these theories could be completely wrong. The experiments could be flawed, resulting in a skewed perception of whether “link echoes” actually exist. Or, there could be some invisible third factor playing a role in determining the strength of those reverberations. If that’s the case, there’s almost nothing we can do to uncover the mystery. All we can do is consider the fact that links can be useful even after they are removed and worry less about preserving the links we have.
Good News and Bad News
For most search marketers, link echoes are a good thing. It means you don’t have to spend time backtracking and checking up on all the links you’ve built. And if you do lose a handful of links (for whatever reason), you can rest easy knowing you’re still getting a benefit from them. Instead of retracing your linking steps, you can spend more time building new links from new sources and diversify your existing strategy.
There is also a potential downside to this algorithm feature. While good links that disappear continue to have positive effects for your site, it’s entirely possible that bad links can continue to have negative effects. For example, if you post a link on an irrelevant site and lose page rank, you could face a slow or impossible recovery even after you take that link down.
If you end up facing a situation like this, the best thing to do is perform a disavowal—a request to Google that they do not take a certain backlink into consideration when attempting to rank your site. This likely circumvents the link reverberation effects since it forces the algorithm to completely ignore the link(s) in question.
Backlinking Strategies That Work
Link echoes aren’t something that requires a major adjustment to your strategy, but they are worth considering. If you can spend less time focused on the past and more time focused on the future, you’ll wind up with better campaign results.
The key takeaway here is that links have a greater long-term significance than we ever thought previously. If you want to make sure you keep positive page ranks, you need to ensure that your strategy only builds links using the most authoritative sources:
Specific niche industry directories
Guest blogs from a range of different high-authority sources
The more effort you put into your link building strategy, the more it will pay off—even after those links disappear.