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Search engine ranking factors can be separated into two primary types: On-page and off-site. On-page signals provide Google with a comprehensive understanding of what a website is about, but off-site signals tell search engines how websites are perceived by users, industry experts, and other reputable webmasters. Improving your site’s off-site signals helps Google recognize your site’s trustworthiness, reputation, and expertise.

Search engines measure your site’s reputation primarily through backlinks, or links to your site from other domains. Links are a voting mechanism, and every backlink you receive is a “vote” or reference for your site. Sites that are authoritative and reputable have votes that count more. A backlink from a prominent site like The New York Times or the Wall Street Journal communicates to search engines that your content has a lot of value and is trustworthy.

Other off-site factors like third-party reviews on social media or platforms like Yelp and Google My Business, as well as unlinked mentions of your brand name, also show Google that others perceive your site as high-quality.

graphic of LinkGraph chart explaining Domain Authority

Unlike on-page SEO, off-site signals are, for the most part, out of the webmaster’s control. You can’t choose when, how, or if a site links to yours, references your brand on their site, or talks about your business on social media. But because off-site factors have such a significant impact on whether Google will rank your site, boosting your off-site signals is essential in improving online visibility and driving organic traffic from search.

There are strategic ways to enhance your site authority, and the most effective comes in the form of white-hat link building. By earning quality links on other trustworthy sites, you can improve your site’s reputation in the eyes of users, other webmasters, and search engine crawlers.

The 3 Key Site Authority Signals that Google Measures

Of the multiple off-site factors that Google's algorithm crawls to evaluate your site authority, some play a more vital role in getting on the first page of Google. The below off-site signals are the primary factors that make for high authority, reputable websites. Focusing on improving them can directly translate into your website earning better results in the SERPs.



In every correlation study of search engine ranking factors versus top search results, backlinks are always the #1 greatest predictor of rankings. The more “votes” that your site has (and the more higher-quality sites that those votes come from) the more likely your site will appear on page 1.

But not all backlinks are created equal. Google looks to several different factors to evaluate the quality of the backlinks your site receives.


The more total PageRank a linking site has, the more PageRank and authority it passes on when it links to your site.

Textual Relevance

The text content of the landing pages that link to your site matters significantly.

“In many experiments I’ve run with building backlinks from massive sites, a link without surrounding relevant text context doesn’t seem to pass nearly the same amount of PageRank as when there is text context and it’s very aligned”
Domain Authority

The higher the domain authority of the linking site, the more valuable the backlink.

What is Domain Authority?

Domain Authority (DA) is a comparative metric created by the company Moz to measure how likely a website is to rank in search results. The score is measured on a 0-100 scale. The higher the domain authority, the more likely a site is to rank.

How does Domain Authority relate to SEO?

Technically, your Domain Authority score is not a Google ranking factor. However, many of the metrics that are used to compute DA are similar to the ranking factors that make up Google’s algorithm. DA is not an absolute metric, but the score is helpful for comparative and benchmarking purposes. Making efforts to raise your DA will likely result in more keyword rankings and increased organic traffic. Your site’s DA is a reflection of your site’s overall reputation.

Anchor Text

The anchor text is another contextual factor that determines how impactful a link will be.

“Think about what type of context each one of these anchor text options offers:
“Click here”
“Yoursite” or “”
Natural backlink profiles usually have at least 30-40% of their anchor text profile referring to their brand name in some way”
Referring Domains

There’s a dampening factor that makes additional links from the same domain pass less PageRank. More referring domains makes for a healthier backlink profile.

Unlinked Mentions

Besides links from publications and online editorials, a natural part of having a strong brand and digital presence is being mentioned in online forums (e.g. Quora, social media sites, etc.)


Branded Traffic / Direct Traffic to your Site

Visitors who go directly to your website or search for it in Google Search are strong quality indicators to Google that your site is reputable and well trusted. Google measures Branded Traffic as the number of people that are searching for your brand via Google each month.

Search engine algorithms use branded and direct traffic as comparative metrics to your competitors. Unlike black hat link building or fake reviews, branded traffic is hard to fake. For this reason it is an effective way to measure your site’s reputation among your industry peers.

Google is able to measure branded traffic through the data it collects in a few ways:

Google Analytics attributes the source and amount of your traffic. It is a very easy way for them to measure your direct traffic.

Google Search looks at the total search volume for search queries containing your brand vs. competitors

graphic of search icon

Google Chrome allows them to measure people navigating to your site directly in the URL bar.

One easy way to increase Branded Traffic is by having assets on your websites that customers regularly access and utilize. This could be anything from a dashboard or internal platform they can get to by logging in somewhere on your website. This forces them to visit often.

graphic showing LinkGraph's software suite tools

At LinkGraph, we have a software suite of free tools that drive tons of branded traffic to our site. Our Bulk Domain Authority Checker and Keyword Search Volume tool are valuable assets that users come back to utilize again and again.

Some examples of possible assets to drive branded/direct traffic:

  • A Learning Center with tutorials and helpful resources
  • Unique collections of information that don’t already exist or are hard to find
  • Convenient tools or resources that can be used or referenced regularly



Reviews are another way that major search engines evaluate the reputation of your site. They are especially important for local businesses that get a lot of traffic from local search and the Map Pack, but we’ve even seen reviews play a meaningful role with rankings for enterprise and corporate clients as well.

The most well-known review sites include Yelp, Google My Business, Trip Advisor, etc. but most industries have their own unique third-party review sites. It’s important for business owners to identify the popular review sites in their industry that compare their products or services to competitors on a regular basis.

“In expert roundups featuring you and your competitors, how high are you in the list? What’s your average score? Google is able to easily parse review scores and the review content themselves because of and the specific review microdata.”

In general, review platforms have a natural tendency toward accumulating negative reviews because most people only leave reviews when they’ve had a bad experience. It’s important to counterbalance this by sending your customers with positive experiences towards the review platforms, and incentivizing them if necessary. It’s easier to maintain a 4.5-star or higher average by targeting customers with positive shopping or service experiences.

Other Weaker Off-Page Factors

In comparison to the above off-site SEO signals, the below factors don't carry as much weight in building your site authority, but are still used to determine your site's rank on search engine results pages.

Social Signals

Google has officially indicated that they are consuming APIs from Facebook and Twitter to ingest this information. From our own correlations studies, we have never seen social signals be a strong ranking factor, but collective likes, shares, or overall social media visibility won’t hurt you. Plus, social media platforms can be used to build your brand and strategically get more traffic to your site. If you’re able to use social media effectively, it can be a great way to increase your traffic and brand awareness (and indirectly improve your SEO).

Traffic from Email Campaigns

Although email outreach will not play a major factor in your rankings, email campaigns can be great for driving traffic back to your site and raising awareness about your brand and digital assets. Like social signals, it's a good way to promote the valuable content on your web pages that may lead to high quality backlinks in the future.

What is Link Building?

Link building is the process of earning links on other reputable sites to boost your own site authority and reputation. There are a variety of link building strategies that SEO experts use, but at its core, link building is a content marketing strategy. By creating valuable content that other sites will want to link to, you can acquire the quality, relevant links needed to have search engines perceive your site as authoritative.

How Important is Link Building as a Google Ranking Signal?

In our correlation studies, site authority (or the strength of a site’s backlink profile) is always the ranking component most correlated with sites that are able to rank on the first page of Google.

“It's true that ranking factors are weighted differently depending on the type of search. Google's algorithm uses varying search models depending on the search intent behind the question. Local searches with the map pack, higher economic value searches with high CPC, informational queries with high search volume, searches where the most relevant results may be rich media like videos/images, and other types of searches all weight ranking factors differently. But across all these variables, a site's backlink profile is consistently one of the most important factors.”

For this reason, link building is always a worthwhile investment for websites of all sizes because of its direct impact on rankings. Building your domain authority with quality backlinks takes a lot of hard work, but it is well understood across the SEO community as one of the most important parts of search engine optimization.

Scaling Link Building Campaigns - How Many Links do I Need to Rank?

The number of links you need in your backlink profile depends on your industry and how big your competitors backlink profiles are. Well-established websites with high domain authority often have hundreds, if not thousands, of referring domains. But those sites have also had a lot of time to accumulate the kind of links that build domain authority and secure top keyword rankings for the long haul.

But don’t get discouraged just comparing the number of referring domains. There are plenty of opportunities for newer sites to build links, because webmasters are always looking for new content. Your site can earn authoritative links as long as you’re willing to do the work of content creation.

A little research can help you find the less competitive keywords that your site stands a good chance of ranking for. We created our Organic Difficulty score to better understand how competitive different keywords are. You can use our Keyword Research Tracker to identify smarter, more realistic target keyword opportunities for your own website.

Backlink Profile Benchmarking

Backlink profile benchmarking is the process of comparing your site to your competitors, and is a great way to understand the number of links your own site needs and from where. For some backlink profiles, 20-30% of the backlinks are from spammy, low-quality domains, from content that’s been syndicated and duplicated, or are just low quality spammy domains regurgitating content. If your link building process results in better links, you may be able to easily surpass your competitors.

Our Backlink Analyzer will help you compare domains and remove the spammy ones. To take a closer look at how your backlink profile measures up against your competitors, use our tool to start your benchmarking process right away.

For local businesses targeting keywords with low Organic Difficulty, 10-20 solid backlinks from quality referring domains can be enough to get decent rankings. For competitive niches like insurance, ecommerce, and high value industries (think Amazon), your most established competitors will have thousands of high quality referring domains that you’ll need to build over the course of a few years. Getting strategic with link building is essential if you ever hope to catch up to them and compete in search.

How to Identify High Quality Sites for Link Building

When it comes to link building, it’s better for your backlinks to come from websites that have strong SEO metrics themselves. Not all links are created equal, and inbound links from the wrong kinds of sites can actually harm your link profile. Google will penalize those websites that appear to be engaging in manipulative or black hat SEO tactics.

When looking for relevant sites for your link building outreach, the key components that make for higher-quality sites include:

  • High Domain Authority
  • Low Spam Score
  • High organic traffic
  • Some traffic from social
  • Topical or industry relevance to your site
  • Healthy backlink profile
  • Outlink profile is do-follow and links to a wide range of sites.
White-Hat vs. Black-Hat Link Building

Link building has a complex history. In the past, spammers and low-quality sites used black-hat link building techniques to manipulate search engines into perceiving their content as high-quality. As a result, Google’s algorithm updates have often focused on identifying these black-hat techniques and penalizing those sites that choose to employ them.

White-hat link building, however, is a safe way to increase site authority, because it uses Google’s favorite thing -- high quality content -- to improve your site’s reputation.

Some webmasters are hesitant to pursue link building because they have been impacted by some of the lower-quality options. But you get what you pay for. Some websites that try to pay someone on Fiverr to programma