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ACRank stands for A-Citation-Rank. It is a very simple measure of how important a particular page is by assigning a number from 0 (lowest) to 15 (highest) depending on the number of unique referring external root domains. Therefore in order for a page or link to have ACRank of 1 or higher it needs to have at least one external backlink. Below you can see the ACRank distribution table showing the minimum number of referring domains for each ACRank level:

ACRank 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Ref Domains 0 1 2 4 8 24 72 216 648 1,944 5,832 17,496 52,488 157,464 472,392 1,417,176

ACRank is a very simple and primitive measure of importance that allows us to prioritise analysis by looking at the data with the highest ACRanks first. However it should be said that in its current design it suffers from a serious drawback: the actual ACRank weight of a backlink is not taken into account, so a page with one backlink of ACRank 1 will have the same ACRank value of 1 just like the other page that has got a backlink with ACRank of 10 (or 15). Clearly the latter page should have got a higher ACRank as being linked to from the more important pages intuitively makes the page they linked to also more important. This drawback is going to be addressed shortly. Despite this limitation ACRank makes it easier to analyse data that is likely to have the highest weight. Meanwhile a concept of ACRank spread is used in an attempt to have better comparison of pages that might have the same ACRank.

ACRank Spread

ACRank spread shows the number of backlinks for the domain, broken down by ACRank. In the example below, the domain has 8024 backlinks with an ACRank of 1, and 1597 with an ACRank of 4.

Rank 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Backlinks 270913 8024 9729 3784 1597 397 87 27 4 2 3 0 0 0 0 0

The table above shows a fairly typical distribution (for a high ACRanked page) - normally the higher the ACRank, the less such backlinks exist. In some cases there are gaps for lower value ACRank, sometimes there are none. The purpose of ACRank spread is to show diversity of backlink ACRanks and thus estimate the value of the URL they point to better, or maybe drill down to see actual backlinks.

Advanced Report(play video)

An Advanced Report provides access to all of the data available on a given domain, subdomain or URL.

Advanced Reports give onscreen access to information about the most important ( by AC Rank ) backlinks, with the full dataset available to download.

Advanced reports are free for registered owners of sites who are able to upload a small verification file. Read more about our Advanced Reports.

Allowance Period

The period of time for which your usage allowances are active. If your subscription is still active after this period, then the usage Allowances will be reset. Allowance periods are usually monthly ( subject to terms and conditions ) but may vary for special subscriptions.

Analysis Options

When an Advanced Report is created or "Force New Analysis" is performed upon it, a set of options are applied to each row by default, which can remove data you may not be interested in - for example, by default, Mentions are removed from Advanced Report. These options can be changed so that future "Force New Analysis" and optionally "Download Backlinks" are subject to the new rules. The "Analysis Options" are applied to Source and Target URLs and can filter on fields such as the Last Crawl Date.

Anchor Text

The text associated with a hyperlink, usually contained between the opening and closing "a" tags. For users, it is the readable, clickable part of the link. With images, anchor text is often defined as the alt text of the link. Search Engines may use this text to help determine the subject matter of the linked-to document.

Annual Subscription

These are subscriptions, often prepaid, that run for approximately a year, with a one year minimum subscription length. Normally, they consist of 12 allowance periods, which are reset on the monthly anniversary of the subscription starting.

API ( Also Light API / Reseller API )

Majestic SEO has three classes of API. The API allows automated querying of our dataset - which is otherwise not permitted.

Our Light API consists of one command - GetIndexItemInfo - which can be used to retrieve headline counts for many domains, subdomains and URLs in our Index.

Our API ( previously called our Enterprise API ) is available with our Platinum Plan for Internal Use Only ( no resale or use in applications ). Larger allowances are available if the Platinum Plan does not fit your requirements.

Our Reseller API facilitates the building of web and public facing applications. Reseller API deals are individually negotiated, and typically cost several thousand pounds a month. Should you be interested in the Reseller API, please contact us to begin discussions.

Backlink(play video)

Also referred to in SEO as an "inlink".

Describing link data is a difficult process. If one page contains five different links to a different page is this one backlink or several?

Generally, for clarity on this site we describe a "backlink" as unique per page - this presents a more easily comparable figure. This approach, however causes difficulties when you look at the data from an anchor text perspective. Each link on a page can contain a different anchor. This means that from an anchor text perspective, the backlink count that made sense above is now less meaningful.

The diffence between a backlink and a unique link can cause confusion. Obviously - there are generally more unique links for a page than backlinks. Due to the ease in which links can be added to some pages, backlink counts tend to be more meaningfull as a statistic than individual link counts. On Majestic SEO, some reports contain unique links, perhaps with anchor text. This often leads to the number of rows returned for a given report being different than the number of backlinks quoted and is quite normal.

Bulk Backlink Checker Limit(play video)

The number of domains you can add at any one time to the "Bulk Backlink Checker" tool. Without an account, it is limited to 5 domains, but increases depending on the level of your subscription plan.

Citation Flow

Citation Flow is one of the Majestic SEO Flow Metrics, which is weighted by the number citations to a given URL, or Domain.

C-subnet / C block / Class C Subnet

In SEO terms, a "Class C subnet" refers to a class-c sized networks, where the last octet ( number separated by dots ) of the IPV4 address is ignored. So if there are three machines, one with IP, one with IP, and one with IP, an SEO expert may say that the machines are hosted on two Class-C subnets.

These terms have subtly different definitions in technical systems networking than in SEO, which can lead to confusion.


A distinct subset of the Internet with addresses sharing a common suffix, e.g "".

Domain Clustering / Linking Domains

Linking Domains refer to the number of unique domains ( e.g. * ) containing at least one linking page to the target URL/domain.

Flow Metrics

Flow Metrics are scores assigned to websites and URLs by algorithms run on Majestic SEO servers during the build of an index. Flow Metrics are expressed as numbers between 0 and 100, the higher the number, the stronger the signal.

Flow Metrics are produced by studying how various metrics alter as they flow through the link graph. This technique provides an indication of how sites compare within the context of the internet ( or, at least, the part of the internet we have crawled and indexed ).

Fresh Index

The Fresh Index contains data from webpages visited recently - currently the last 90 days. These links tend to have a higher probability of being live than links found in the historic index.

First Crawled

This is the date that the link was first located.

Please Note: Due to limitations of storage, The first crawl date degrades in accuracy after 150 days.

Historic Index

The Historic Index is the largest index of backlinks we know about on the web. The "Historic Index" started on 06 Jun 2006 and contains information on Trillions of Linking Relationships.

Index Item Units

These are fully explained in the API documentation and are not applicable to the web-only services.

IP Address

A number assigned to each computer's or other device's network interface(s) which are active on a network supporting the internet protocol, in order to distinguish each network interface ( and networked device ) from every othet network interface anywhere on the network. In IPV4 - the most common form of Internet addressing, this is normally shown in dotted form,

Link Profile

A link profile is a scatter plot, produced by drawing the Trust Flow and Citation Flow for the referrers to a given domain or URL.

Last Crawled

This is the last date the page containing a given link was crawled.

Linked to Page vs Link

In the context of pages vs links, "page" refers to a URL that was actually crawled successfully and included in the index. Backlinks are always referring pages because we could not know what they link to if they were not crawled successfully.

"Link" refers to URLs that were found to be referenced from one or more of the crawled pages, but the link itself has not been crawled yet (or the crawl was attempted but it failed for one reason or another).

Long Domain

Long domain is a root domain with subdomain, eg: or Both of these are long domains of the root domain

Max. analysable backlinks

Each subscription plan has a cap on the total number of backlinks which can be reported on in a given period within the advanced reports. By way of example, the Silver subscription lets you analyse 5 million backlinks a month. So if you want to track three sites which each have 1.5 million backlinks, then this would mean that trying to analyse a fourth site in the same month of that size would not be possible, as it would take you over your limit. However, you may still be able to analyze the links to just the URL or the subdomain that interests you. Once you have analysed a domain, subdomain or URL in any given allowance period, you will not be charged again if you "reanalyse" the same data - for example by filtering the data in the options screen.

Referring Domain

Referring domain, also known as "ref domain", is a domain from which a backlink is pointing to a page or link.

Referring IP's

Many domains ( websites ) can be hosted on one IP address. A Referring IP refers to an IP which may host one or more websites, that may contain one or more links to a given target URL or Domain.

Referring Subnet

This is an abbreviation for "Referring C-subnets".

In the Majestic SEO system, Multiple counts are calculate for links, deduplicating links across pages ( which we refer to as backlink count ), across domains ( the domain count ), and across c-subnets. The c-subnet count is useful, as it is possible for the same class c subnet to be used by one, or associatted organisations. For larger sites, counting the unique linking relationships across C-Subnets can be useful

Retrieval Units

Retrieval units are fully explained in the API documentation and are not applicable to the web-only services.

Root Domain

Also known as Second Level Domain, and previously called "Short Domain" on Majestic.

The shortest form of the domain without specifying any subdomains, ie:

Short Domain

We now use "Root Domain" to describe this concept. The term "Short Domain" should be considered deprecated.

Source flags

Source flags are designed to differentiate between different types of links. The following source flags are currently in use:

Source Flag Description
Images Set if unique link was an image
NoFollow Set if unique link was marked as nofollow either via META tag or rel="nofollow"
Frame Set if unique link was used in FRAME/IFRAME tags
Redirect Set if source URL redirected (using HTTP response codes 301, 302 or META Refresh based redirect) to target location.
Deleted (or OldCrawl) Set if upon recrawl of that page it was established that the unique link found there in previous crawls was deleted. This often happens when a backlink from the homepage goes into one of the deeper pages as new items take real estate on that page.
AltText Two cases:
1. If anchor text is present: it was taken from alt/title attributes of an A tag.
2. If anchor text is NOT present: target URL was found in normal text on the page - in essense it was mentioned there. Such mentions can present a good link building opportunity.
Mentions Mentions are references to domain names or URLs that we find in plain text. This is done only for domains other than the one referred to.

Using Analysis Options it is possible to exclude/include unique links with specific source flags.

Mentions are references to domain names or URLs that we find in plain text. This is done only for domains other than the one referred to.

Standard Report(play video)

It is possible to generate a standard report for any site in our Fresh Index or Historic Index. A Standard Report contains information about the most important ( by AC Rank ) backlinks. The amount of backlinks shown vary according to the subscription plan.

Standard Report Backlinks

A term previously used to describe Standard Report maximum rows.

Standard Report maximum rows

This is the maximum number of rows of data that will be provided in a Standard Report. It changes depending on your subscription. In a Silver subscription, for example, it is set at 7,500 rows of data. This means that if there are less than 7,500 rows of data available for a given report, we will return ALL of the rows of data to you within the report, but if the index contains more than 7,500 rows of data, then the report will only contain 7,500 rows of data generated from the Top Backlinks. The Standard Report excludes links that are recrawled and flagged links as deleted, and links which are flagged as mentions.

The Standard Report contains link data at a unique anchor text level, of which there may be many in one "backlink". For this reason, the counts in a Standard Report may differ from the backlinks totals quoted elsewhere in the site.

Top Level Domain

Top Level Domain is the highest level of domains in the hierachical Domain Name System of the Internet. The top-level domain names are installed in the root zone of the name space. For all domains in lower levels, it is the last part of the domain name, that is, the last label of a fully qualified domain name. For example, in the domain name, the top level domain is "com".

Top Backlinks

"Top Backlinks" are an attempt to list the most popular pages linking into the target URL or Domain in question. Historically, AC Rank is used to calculate the relative importance of pages, however, Majestic SEO reserve the right to enhance the metrics used to calulate page importance at any time.

Trust Flow

Trust Flow is one of the Majestic SEO Flow Metrics, which is weighted by the number of clicks from a seed set of trusted sites to a given URL, or Domain.


Whilst we hope to provide the best possible user experience to our userbase, this Glossary may contain errors and ommisions. This page is intended to provide an overview of some of the techniques which may be used in the delivery of data from Majestic SEO - but please note that the provision of any service may be subject to more frequent review than this text. Use of our services is subject to the acceptance of our Terms and Conditions.