30 Link Building Terms Every SEO Should Know

The Link Building Glossary

Link building has its own vocabulary — terms that are used constantly in SEO discussions but rarely defined clearly. This glossary covers the 30 most important terms, from foundational concepts to technical specifics, so you can follow any link building conversation with confidence.

A–E

Anchor Text — The visible, clickable text of a hyperlink. Anchor text signals to search engines what the linked page is about. Over-optimized exact-match anchor text (repeating the same keyword across many links) can trigger Google's spam filters.

Authority — The measure of a site's or page's credibility and link equity, as estimated by third-party tools (Domain Authority, Domain Rating) or implied by Google's internal signals. Higher authority generally means more valuable links.

Backlink — An inbound link from one website to another. Also called an inbound link or incoming link. Backlinks are one of Google's primary ranking signals.

Broken Link Building — A tactic where you identify dead links on other websites and suggest your content as a replacement, earning a backlink while helping the site owner fix a problem.

Citation — A mention of your brand, content, or website — either with or without a hyperlink. Unlinked citations (brand mentions without a link) may still contribute to brand authority signals.

Crawl — The process by which search engine bots visit web pages to index their content and follow links. A page must be crawled before any links it contains can be processed.

Domain Authority (DA) — A metric created by Moz (0–100) estimating a domain's ranking potential based on its backlink profile. Not a Google metric; used as a proxy for site quality.

Domain Rating (DR) — Ahrefs' metric (0–100) measuring the strength of a domain's backlink profile relative to others in Ahrefs' index.

Dofollow Link — The default state of an HTML link that passes link equity from the linking page to the destination. No special attribute needed — links are dofollow unless specified otherwise.

Earned Link — A backlink acquired without direct outreach, because another site found your content valuable enough to reference independently. The gold standard of link building.

F–L

Guest Post — An article written by an outside contributor and published on another site, typically in exchange for a backlink to the author's site.

Index — Google's database of web pages. A page must be indexed before it can rank. Links from indexed pages pass equity; links from non-indexed pages may not.

Internal Link — A link from one page on your site to another page on the same site. Internal links distribute link equity across your site and help Google understand your content structure.

Link Equity — Also called "link juice." The value or authority passed from one page to another through a hyperlink. The amount depends on the linking page's authority, the number of outbound links on that page, and whether the link is dofollow.

Link Exchange — A reciprocal linking arrangement where two sites agree to link to each other. Legitimate when done between relevant sites at reasonable volume; manipulative when done at industrial scale with irrelevant sites.

Link Farm — A network of pages created primarily to generate backlinks, with no real content value. Links from link farms are discounted or penalized by Google.

Link Profile — The full collection of backlinks pointing to a website, including their sources, anchor text, link types, and quality distribution.

Link Velocity — The rate at which a site acquires new backlinks over time. An unnatural spike in link velocity can trigger algorithmic scrutiny.

M–R

Manual Action — A Google penalty applied by a human reviewer when a site is found to violate Google's Webmaster Guidelines. Link-related manual actions are among the most common and can result in ranking suppression or deindexing.

Niche Edit — A link inserted into existing, already-published content on another site, rather than in a new piece of content. Also called a curated link or contextual link insertion.

Nofollow Link — A link with the rel="nofollow" attribute, originally intended to prevent link equity from passing. Google now treats nofollow as a hint rather than a directive.

PageRank — Google's original algorithm for evaluating page authority based on the quantity and quality of inbound links. While no longer publicly displayed, PageRank concepts underpin how link equity flows through the web today.

PBN (Private Blog Network) — A network of websites created specifically to build links to a target site, typically violating Google's guidelines. Links from PBNs risk manual penalties.

Referring Domain — A unique domain that links to your site. Ten links from the same domain count as one referring domain. Referring domain count is a more meaningful metric than total link count.

Resource Page — A page that curates and links to the best external resources on a given topic. Resource pages are a common target for legitimate link building outreach.

S–Z

Skyscraper Technique — A link building method involving finding content with many backlinks, creating a superior version, and reaching out to the sites linking to the original to suggest the improved version.

Spam Score — Moz's metric indicating the percentage of sites with similar link profiles that have been penalized by Google. Used to flag potentially risky link sources.

Sponsored Link — A link with rel="sponsored", indicating it was placed as part of a paid arrangement. Required by Google's guidelines for any paid link placements.

Toxic Backlink — A backlink from a low-quality, spammy, or manipulative source that may harm your site's rankings. Can be addressed through removal requests or the Google Disavow Tool.

UGC Link — A link with rel="ugc" (user-generated content), indicating it was posted by a user rather than editorially placed. Common in comments, forums, and community platforms.

White Hat Link Building — Link acquisition tactics that comply with Google's guidelines: earning links through quality content, legitimate outreach, and genuine relationships, rather than manipulation or payment.

For a deeper introduction to link building concepts, see What Is Link Building? The Complete Beginner's Guide. For how Google actually uses these signals, see How Google Really Uses Backlinks to Rank Websites.