Referrer spam (also known as referral spam, log spam or referrer bombing) is a kind of
spamdexing
Spamdexing (also known as search engine spam, search engine poisoning, black-hat search engine optimization, search spam or web spam) is the deliberate manipulation of search engine indexes. It involves a number of methods, such as link building ...
(
spamming
Spamming is the use of messaging systems to send multiple unsolicited messages (spam) to large numbers of recipients for the purpose of commercial advertising, for the purpose of non-commercial proselytizing, for any prohibited purpose (especial ...
aimed at
search engine
A search engine is a software system designed to carry out web searches. They search the World Wide Web in a systematic way for particular information specified in a textual web search query. The search results are generally presented in a ...
s). The technique involves making repeated
web site
A website (also written as a web site) is a collection of web pages and related content that is identified by a common domain name and published on at least one web server. Examples of notable websites are Google, Facebook, Amazon, and Wikipe ...
requests using a fake
referrer
In HTTP, "" (a misspelling of Referrer) is an optional HTTP header field that identifies the address of the web page (i.e., the URI or IRI), from which the resource has been requested. By checking the referrer, the server providing the new web p ...
URL to the site the spammer wishes to advertise.
Sites that publish their access logs, including referrer
statistic
A statistic (singular) or sample statistic is any quantity computed from values in a sample which is considered for a statistical purpose. Statistical purposes include estimating a population parameter, describing a sample, or evaluating a hypo ...
s, will then inadvertently link back to the spammer's site. These links will be
indexed by
search engines
A search engine is a software system designed to carry out web searches. They search the World Wide Web in a systematic way for particular information specified in a textual web search query. The search results are generally presented in a ...
as they crawl the access logs, improving the spammer's
search engine ranking
Search engine optimization (SEO) is the process of improving the quality and quantity of Web traffic, website traffic to a website or a web page from web search engine, search engines. SEO targets unpaid traffic (known as "natural" or "Organ ...
.
Except for polluting their statistics, the technique does not harm the affected sites.
At least since 2014, a new variation of this form of spam occurs on
Google Analytics
Google Analytics is a web analytics service offered by Google that tracks and reports website traffic, currently as a platform inside the Google Marketing Platform brand. Google launched the service in November 2005 after acquiring Urchin.
As o ...
. Spammers send fake visits to Google Analytics, often without ever accessing the affected site. The technique is used to have the spammers' URLs appear in the site statistics, inducing the site owner to visit the spam URLs. When it is the case that the spammer has never visited the affected site, the fake visits are also called Ghost Spam.
Technical solutions
As with
e-mail
Electronic mail (email or e-mail) is a method of exchanging messages ("mail") between people using electronic devices. Email was thus conceived as the electronic ( digital) version of, or counterpart to, mail, at a time when "mail" meant ...
spam, referrer spam may be filtered or blocked. A website operator may mitigate referrer spam by preventing search engine spiders from crawling the site logs by moving them to a non-public area such as a password-protected area, by using
a robot exclusion file, or by appending the
nofollow
nofollow is a setting on a web page hyperlink that directs search engines not to use the link for page ranking calculations. It is specified in the page as a type of link relation; that is: <a rel="nofollow" ...>. Because search engines ...
value to the links.
Spammers that target third party analytics directly can pollute statistics, but do not consume the affected site's resources. Filtering referrer spam from analytics tools will hide it from reports. However, spammers that do visit the affected site will consume server bandwidth. To prevent this misuse, they can be blocked using various techniques, such as by blacklisting a list of
IP addresses
An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface ident ...
.
Non-technical solutions
Because the
.htaccess solutions require technical expertise, several developers have created tools for non-technical people to block the spam more automatically, specifically for Google Analytics.
See also
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Notes
External links
Referrer Spam Blacklistby Matomo - a Community-contributed list of referrer spammers under Public Domain (550+ domains as of October 2017).
{{DEFAULTSORT:Referrer Spam
Black hat search engine optimization