Authority & Domain Metrics
These are the numbers used to describe how strong a domain is, and they're the figures you'll see quoted first in any listing. None of them is a Google metric — they're third-party estimates — so it's worth understanding what each actually measures rather than treating a single score as the final word.
Domain Rating (DR) — An Ahrefs metric from 0 to 100 that measures the strength of a domain's backlink profile on a logarithmic scale. It's the most widely quoted authority number in the aged-domain market. See our full guide to Domain Rating.
URL Rating (UR) — Ahrefs' page-level counterpart to DR, scoring the link strength of a single URL rather than the whole domain. Useful when a specific page carries most of a domain's value. See URL Rating.
Domain Authority (DA) — Moz's competing 0–100 authority score. It predicts ranking ability but is calculated differently from DR, so the two rarely match. See Domain Authority vs Domain Rating.
Trust Flow & Citation Flow (TF/CF) — Majestic's paired metrics that split link quality (Trust Flow) from link quantity (Citation Flow); the ratio between them exposes manipulated profiles. See Trust Flow and Citation Flow.
Organic Traffic & Traffic Value — The estimated monthly search visits a domain earns and the equivalent cost of buying that traffic through ads. Real traffic is one of the hardest signals to fake. See domain traffic and traffic value.
Spam Score — A metric (popularised by Moz) that estimates how likely a domain is to be penalised, based on patterns associated with spammy sites. A high score warrants a closer look. See domain spam score.
Link & Backlink Terminology
Backlinks are the foundation of domain authority, so this is the vocabulary you'll lean on most when judging whether a domain's strength is real. These terms describe where a domain's authority comes from and how it flows.
Backlink — A link from another website to yours. The full set of them, taken together, forms your backlink profile, which is what authority metrics are built on.
Referring Domain — A unique website that links to you. Because one site can link many times, referring domains matter more than raw backlink counts. See referring domains.
Authority Link — A backlink from a high-authority, trusted site. A few of these outweigh hundreds of weak links. See authority links.
Link Equity ("link juice") — The ranking value passed through a link from one page to another. It's the currency that makes backlinks valuable. See link equity.
DoFollow / NoFollow — Whether a link passes authority (dofollow) or explicitly doesn't (nofollow). A natural profile mixes both. See dofollow vs nofollow.
Anchor Text — The clickable words in a link and a key relevance signal; an over-optimized anchor profile is a common penalty trigger. See anchor text.
Domain Lifecycle Terms
Understanding how a domain becomes available explains where you're buying from and how much competition and risk to expect. These terms trace a domain's journey from active registration to being available again.
Expired Domain — A previously registered domain whose owner didn't renew it. It may retain backlinks and authority from its earlier life. See expired domains.
Dropped Domain — A domain that has passed through the full expiry process and been released by the registry for anyone to register again. See expired vs dropped vs backorder.
Backorder — A paid pre-order placed with a service that attempts to register a domain the instant it drops, on your behalf.
Domain Auction — A marketplace where expiring or premium domains are sold to the highest bidder, such as GoDaddy Auctions or NameJet. See domain auctions.
Domain Age — How long a domain has existed since first registration; a mild trust signal that's often overstated. See does domain age matter.
Strategy & Risk Terms
Finally, this is the language of putting domains to work — and of the risks that can make a strong-looking domain worthless. These are the terms that separate a good buy from an expensive mistake.
PBN (Private Blog Network) — A network of sites built on aged domains to funnel links to a main "money" site. Powerful but risky if Google detects the footprint. See PBN domains.
301 Redirect — A permanent redirect that passes the majority of link equity to a new URL; the standard way to point an aged domain's authority at your site. See 301 redirects for domain authority.
Niche Relevance — How closely a domain's topic and backlinks match your project; relevant authority is worth far more than generic authority. See niche relevance.
Penalty — A manual or algorithmic action by Google that suppresses a domain's rankings, usually for guideline violations by a past owner. See domain penalties.
Deindexed — Removed from Google's search index entirely, meaning the domain cannot rank at all — the worst outcome to inherit. See how to check for deindexing.
Disavow — Telling Google, via a disavow file, to ignore specific toxic backlinks pointing at a domain you own. See the disavow file.