Link Building FAQ & Glossary: Every Term Explained
Link building has its own dense vocabulary, and confusing the terms will cost you — either in wasted budget on tactics that don’t work, or in misreading your metrics. This glossary covers every core term a working SEO or content strategist needs to know, organized by concept area so the connections between ideas are clear, not just alphabetical.
Whether you’re evaluating a vendor’s pitch, auditing your own backlink profile, or briefing a new team member, these definitions reflect how practitioners — including the team at Salterra — actually use these terms in real client work.
Backlinks: The Core Concepts
Backlink
A backlink is any hyperlink on an external website that points to a page on your site. From your perspective as the recipient, it’s an inbound link. From the linking site’s perspective, it’s an outbound link. Backlinks are the primary mechanism by which Google’s PageRank algorithm historically measured authority — the assumption being that editorially placed links signal that other sites consider your content worth referencing. Volume matters less than quality; a single backlink from a trusted, topically relevant source typically outperforms dozens of links from low-quality directories.
Referring Domain
A referring domain is any unique domain that hosts at least one backlink to your site. If a single site links to you from five different pages, that counts as one referring domain but five backlinks. Referring domains are generally considered a more meaningful metric than raw backlink count, because getting 50 links from 50 different independent sites is a much stronger signal than 50 links from the same domain. Growth in unique referring domains is one of the clearest early indicators that a link acquisition campaign is working.
Link Equity (Link Juice)
Link equity — sometimes called “link juice” — is the value or authority that passes from a linking page to the page being linked to. It is not a metric you can read directly; it is a conceptual model for how PageRank flows through the web. A page with many high-quality backlinks of its own has more equity to pass. That equity is then divided among all the outbound links on the page, which is why a link from a page with hundreds of outbound links is worth less than a link from a page with only a few. Internal links also pass equity, which is why internal linking architecture matters alongside external link building.
Link Velocity
Link velocity describes the rate at which a site acquires new backlinks over time. An unnaturally sudden spike — say, hundreds of new links appearing in a single week after months of flat growth — can trigger algorithmic scrutiny or manual review. Equally, a site that built links at scale and then suddenly stops may send a signal that the activity was artificial. Sustainable link building produces a consistent, gradual velocity that mirrors how a genuinely popular site earns links organically.
Link Attributes: Dofollow, Nofollow, and Beyond
Dofollow Link
A dofollow link is the default state of any hyperlink without a qualifying rel attribute. Despite the name, “dofollow” is not an actual HTML attribute you add — it simply means the link has no instruction telling search engines to ignore it. Search engines follow dofollow links, crawl the destination, and pass link equity to it. When SEOs talk about “earning links,” they almost always mean earning dofollow links, because these are the ones that move authority metrics.
Nofollow Link
A nofollow link carries the rel=”nofollow” attribute, originally introduced by Google to give publishers a way to link to user-generated content or paid placements without implicitly endorsing them. Google’s official position is that nofollow is treated as a “hint” rather than a directive, meaning the link may or may not pass equity depending on context. In practice, a mix of dofollow and nofollow links in a backlink profile looks natural — a profile of 100% dofollow links can appear manipulated. Nofollow links still drive referral traffic and can contribute to brand visibility.
UGC and Sponsored Attributes
Google expanded link rel attributes to include rel=”ugc” (user-generated content) for links in comments, forum posts, and similar user contributions, and rel=”sponsored” for paid placements, including affiliate links. Using sponsored on paid links is Google’s required practice — failing to do so on compensated placements violates their guidelines. These attributes can be stacked: rel=”nofollow sponsored” is valid and appropriate for a paid link placed in a context where nofollow is standard practice.
Authority Metrics: Domain Authority, Domain Rating, and More
Domain Authority (DA)
Domain Authority is a proprietary score developed by Moz, ranging from 1 to 100, that predicts how likely a domain is to rank in search results based on its backlink profile. It is a third-party metric — not a Google signal — and should be used as a comparative benchmark, not an absolute measure of SEO value. A DA of 40 is meaningful in the context of a competitor with DA 20, but says nothing on its own about whether a specific link from that domain will move your rankings. DA is useful for prospect scoring during outreach, but it’s not the only factor worth evaluating.
Domain Rating (DR)
Domain Rating is Ahrefs’ equivalent metric, also on a 1–100 scale, measuring the strength of a domain’s backlink profile relative to all other sites in Ahrefs’ database. Like DA, it is a third-party approximation and not a Google metric. DR tends to update more frequently than DA and is based on a slightly different methodology, so the same site may show different scores on each platform. At Salterra, when evaluating link prospects during outreach campaigns, we look at both DA and DR alongside actual traffic estimates and topical relevance — no single number tells the full story.
URL Rating (UR) and Page Authority (PA)
While DA and DR measure domain-level strength, URL Rating (Ahrefs) and Page Authority (Moz) measure the link strength of a specific page. A link from a high-DR site’s homepage passes more equity than a link from a deep, rarely-linked internal page on the same domain. When evaluating guest post opportunities or editorial link placements, check the specific page’s UR or PA alongside the domain-level metrics — a weaker page on a strong domain can still outperform a strong page on a weaker domain, but not always.
Anchor Text
Anchor Text Defined
Anchor text is the clickable, visible text of a hyperlink. From an SEO standpoint, anchor text sends a relevance signal to search engines — a link with the anchor “best running shoes for flat feet” tells Google something about the destination page’s content. Over-optimization of anchor text (pointing too many links to a page using exact-match keyword anchors) is one of the clearest signals of manipulative link building and is associated with ranking penalties. Natural backlink profiles contain a mix of branded anchors (“Salterra Digital Services”), partial-match phrases, generic anchors (“click here,” “read more”), and bare URLs.
Anchor Text Types
Understanding the categories helps you audit your own profile and avoid patterns that look engineered:
- Exact match: The anchor is the precise keyword you want to rank for. Effective in small doses; risky in large doses.
- Partial match: The anchor contains the keyword alongside other words (“a guide to link building strategies”). More natural-looking.
- Branded: Uses your company or domain name. Should form the largest share of a healthy backlink profile.
- Naked URL: The URL itself appears as the anchor text. Common in editorial mentions and press coverage.
- Generic: Non-descriptive text like “here,” “this article,” or “source.” Normal and expected in a natural profile.
Link Building Tactics: Common Methods and Their Terms
Guest Post
A guest post is a piece of content written and published on a third-party site in exchange for authorship credit and, typically, a backlink to the contributor’s site. When editorial standards are high and the content is genuinely useful to the host site’s audience, guest posting is a legitimate and widely used tactic. When it becomes a link-for-hire scheme where the “editorial” site exists purely to sell link placements, Google considers it a violation of its spam policies. The line is transparency and genuine value — an article you’d be proud to publish under your own name versus a placeholder piece designed only to launder a link.
Digital PR
Digital PR is the discipline of earning editorial backlinks through newsworthy stories, original data, expert commentary, and media outreach. Rather than asking a site to publish your content, digital PR pitches journalists and editors with material worth covering — a proprietary survey, a unique data visualization, or a compelling expert perspective. The resulting links come from news sites, magazines, and authoritative publications, often with high domain authority and editorial weight. This approach scales well for brands with genuine stories to tell and is increasingly the gold standard for earning high-quality links without risking Google’s link spam guidelines.
HARO and Expert Sourcing
Help a Reporter Out (HARO) and similar platforms (Connectively, Qwoted, ProfNet) connect journalists seeking expert sources with practitioners willing to provide commentary. A useful quote or data point in an article earns a mention — often a dofollow link — from a credible publication. The tactic requires consistent monitoring and fast, specific responses. Generic quotes rarely get used. This is one of the cleaner link-earning methods available because the link emerges from genuine journalistic need rather than any transactional arrangement.
Broken Link Building
Broken link building involves finding pages on other sites that link to content that no longer exists (resulting in a 404 error), then offering your own relevant content as a replacement. The pitch is genuinely helpful — you’re alerting the site owner to a problem and offering a solution in one message. Effectiveness depends on finding broken links on pages with meaningful authority and having content that is a close substitute for what was originally linked. It’s time-intensive but produces clean, editorially earned placements.
Link Reclamation
Link reclamation is the process of recovering links you’ve already earned but that are no longer passing equity. Common scenarios include brand mentions without a link (unlinked mentions), links pointing to pages that have since been redirected or deleted, and links where the rel attribute has been changed to nofollow since your page was first cited. Reclamation campaigns often produce quick wins because the site has already signaled it values your brand or content — you’re asking them to complete or restore a citation, not request a new one from scratch.
Risky and Gray-Area Tactics
Private Blog Network (PBN)
A Private Blog Network is a collection of websites — often built on expired domains that already carry backlink equity — controlled by a single operator and used exclusively to pass links to target sites. PBNs are explicitly against Google’s guidelines and, when detected, result in manual actions that can remove the target site from search results entirely. The appeal is control: you can place any anchor text, on any page, pointing anywhere, without the friction of outreach. The risk is existential. Salterra does not use PBNs for client work, and we advise against any tactic that requires hiding a link’s origin from the site receiving it.
Link Farm
A link farm is a site or network of sites created for the sole purpose of hosting outbound links. The content is thin or nonsensical, the links are numerous, and the intent is purely to manipulate rankings. Link farms have been targeted by Google algorithm updates since at least the early Panda/Penguin era and provide essentially no value in modern link building. A backlink profile full of link farm placements is a liability — it requires a disavow campaign to clean up and may actively suppress rankings.
Tiered Link Building
Tiered link building is a strategy where you build links to your links — pointing low-quality or automated links at the pages that already link to your target site, rather than at the target site directly. The theory is that powering up tier-one links amplifies the equity they pass. In practice, the tactic is associated with spam-heavy operations and, at scale, leaves footprints that algorithmic and manual review can detect. It blurs into PBN territory quickly and carries the same risks.
Link Auditing and Profile Health
Toxic Links and Disavow
Toxic links are backlinks from sources that Google may interpret as manipulative or low-quality — link farms, hacked sites, foreign-language spam directories, and irrelevant auto-generated content. If your site has accumulated toxic links from a prior link building campaign or through negative SEO, Google’s Disavow Tool allows you to submit a file of domains or URLs you want Google to ignore when evaluating your backlink profile. The disavow process is a last resort, not a routine maintenance task, and should be approached carefully — removing legitimate backlinks from your disavow list after the fact is possible but slow.
Link Intersect
Link intersect analysis identifies sites that link to several of your competitors but not to you. If a domain consistently references the top three players in your niche and you’re absent, that domain is a high-probability outreach target — they’re already covering your space and have demonstrated a willingness to link to relevant resources. Most major backlink tools (Ahrefs, Moz, SEMrush) include a link intersect feature specifically for this kind of gap analysis.
NAP Citations (Local Link Building)
For local businesses, citations — mentions of Name, Address, and Phone number (NAP) on directories, review sites, and local media — function as a form of link building specific to local search. Consistency of NAP data across platforms signals to Google that the business is legitimate and well-established. Structured citations on platforms like Google Business Profile, Yelp, and industry-specific directories contribute to local ranking signals even when the mention is a nofollow link or no link at all.
Frequently Asked Questions
What is the difference between a backlink and a referring domain?
A backlink is a single hyperlink from an external page to your site; a referring domain is any unique domain that hosts at least one of those links. One referring domain can produce multiple backlinks if the same site links to you from several different pages. Referring domains are the more important growth metric because 50 links from 50 unique independent sites signals far more authority than 50 links from a single domain.
Does nofollow still count for SEO?
Google officially treats nofollow as a "hint" rather than a hard directive, meaning it may choose to pass some equity through nofollow links depending on context — but in most cases, nofollow links do not pass significant ranking authority. They still have value: they drive referral traffic, contribute to a natural-looking link profile, and can increase brand exposure. A healthy backlink profile includes a mix of dofollow and nofollow links rather than either extreme.
How do Domain Authority and Domain Rating differ from Google's actual ranking signals?
Domain Authority (Moz) and Domain Rating (Ahrefs) are third-party metrics calculated from each tool's own crawled index of the web — neither is a Google metric, and Google does not use them directly. They are useful approximations for comparing sites, scoring outreach prospects, and tracking progress over time, but they can diverge significantly from actual ranking power depending on factors those metrics don't capture, including content quality, technical health, and entity authority in Google's own systems.
What makes an anchor text profile look unnatural?
The clearest signal of an engineered anchor text profile is a disproportionately high percentage of exact-match keyword anchors — particularly if the same keyword anchor appears repeatedly across unrelated sites. Natural profiles are dominated by branded and generic anchors because most people who link to a resource use the site's name or a generic phrase, not a keyword crafted to help the page rank. Auditing your anchor text distribution in Ahrefs or SEMrush and comparing it against top-ranking competitors in your niche gives you a practical benchmark for what normal looks like in your space.
Is guest posting still a legitimate link building tactic?
Yes, when done with genuine editorial value in mind. Google's concern is with guest posts placed on sites that exist purely to sell links — so-called "link insertion" sites with thin content and no real audience. A guest post published on a site with an engaged readership, editorial standards, and topical relevance to your niche is a legitimate link acquisition method. The test is straightforward: would you write and publish this article even if it carried no backlink? If yes, it's editorial. If no, it's likely the kind of transaction Google targets.
What is link velocity and why does it matter?
Link velocity is the rate at which your site acquires new backlinks over time. A sudden, unnatural spike — especially one not tied to any real content event, press coverage, or product launch — can look manipulative to search algorithms. Sustainable link building produces a gradual, consistent velocity that reflects real-world content and PR activity. Monitoring your link velocity in tools like Ahrefs or Moz over rolling 30- and 90-day windows helps you spot both suspicious acquisition patterns and opportunities to capitalize on earned-media moments while they're fresh.
Terry has 30+ years in software and SEO. He’s the founder of Salterra Digital Services and SEO Spring Training, host of the Roundtable SEO Mastermind, and lead instructor at SEO University — teaching the exact tactics his team uses on client work.
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