More recently, Google has actively penalized the rankings of websites who have attempted such overuse of these techniques—often referred to as over-optimisation—in their link building. Google’s regular Penguin updates are one such example. Knowing which link building techniques to avoid and stay within Google’s guidelines is an important subject that we’ll discuss later in this guide.
We don’t know the full algorithm that Google uses to determine its search results—that’s the company’s “secret sauce.” linksexpert Despite that fact, the general consensus among the SEO community (according to the 2015 Moz search ranking factors survey) is that links still play a big role in that algorithm. They represent the largest two slices of the pie chart below.
Weighting of thematic clusters of ranking factors in Google
Domain-Level Link Features
(e.g. quantity of links to the domain, trust/quality of links to the domain, domain-level PageRank, etc.)
Page-Level Link Features
(e.g. PageRank, TrustRank, quantity of link links, anchor text distribution, quality of link sources, etc.)
Page-Level KW & Content Features
(e.g. TF*IDF, topic-modeling scores, on content, content quantity/relevance, etc.)
Page-Level, Keyword-Agnostic Features
(e.g. content length, readability, uniquness, load speed, etc.)
Domain-Level Brand Features
(e.g. offline usage of brand/domain name, mentions of brand/domain in news/media/press, entity association, etc.)
User, Usage, & Traffic Query Data
(e.g. traffic/usage signals from browsers/toolbars/clickstream, quantity/diversity/CTR of queries, etc.)
(e.g. quantity/quality of tweeted links, Facebook shares, Google +1s, etc.)
Domain-Level Keyword Usage
(e.g. exact match keyword domains, partial-keyword matches, etc.)
Domain-Level, Keyword-Agnostic Features
(e.g. domain name length, extension, domain HTTP response time, etc.)
It is generally accepted that if all other factors are equal, the volume and quality of links pointing to a page will make the difference between rankings. Having said that, with recent moves from Google, including the release of Penguin updates and its push of Google+, there is speculation that the impact of links is being reduced and replaced with social signals such as tweets or +1s.
For now, though, there is little doubt that if you get high-quality links to your website, it will help you rank better and get more traffic (we’ll talk more about what makes a “good-quality” link in Chapter 2). We’ve mentioned “high-quality” a few times, now, and there’s a good reason: The focus on quality is increasing as Google becomes ever more sophisticated at filtering out low-quality links. This directly impacts SEOs, as they need to make sure the link building techniques they choose focus primarily on that quality.
What you need to know about nofollow
There is an attribute that can sometimes be applied to links called the “nofollow” attribute. If added, you will not notice any difference if you’re a user. But, if you look at the code of the link, it will look slightly different:
<a href=”http://www.example.com” rel=”nofollow”>Example</a>
Note the addition of rel=”nofollow”. This tells Google not to pass any PageRank across this link to the target URL. Effectively, you’re telling Google not to trust this link and to discount it from consideration. Therefore, it should not help the target URL to rank any better.
The main reason a site might use nofollow relates to scenarios in which that site lacks total control over the links that are added to its pages. In other words, they don’t want to show Google a vote of confidence when they don’t know whether or not they actually are confident. This is more common than you’d expect; here are a few examples:
Guest book comments
Editable Wiki pages (e.g. Wikipedia)
Guest post signatures
Users can freely add links to each of these places, and because of their size, it isn’t really practical to moderate every single one of those links. So, in order to deter link spammers from taking advantage of a site’s PageRank, the site will often choose to apply the nofollow attribute to all links posted by other users.
Another use for the nofollow attribute is for advertisers to use on links that have been paid for. So, if you buy an advertising banner on a website which links to you, Google says that the nofollow attribute should be added so that they know not to pass any PageRank across that link. The idea here is that you shouldn’t benefit in the organic results by buying advertisements that include links on other websites.
More recently, Google has expanded this concept to included optimized links in press releases, article directories, and advertorials. These are all examples where the use of nofollow is entirely appropriate.
In terms of your work, you should know that links that have the nofollow attribute applied will probably not help your organic search rankings as directly as followed links. That isn’t to say they’re not worthwhile. After all, typical users don’t notice whether a link is nofollowed or not, and may actually click through and visit your website even if it is. That is, after all, the point of buying advertisements online. That being said, for the purposes of link building, you want most of your links to be followed and therefore counted by Google. Looking for a way to indentify followed versus nofollowed links on a website? You can use the MozBar to highlight these links on any site.