||This article possibly contains original research. (July 2010)|
Referrer spam (also known as log spam or referrer bombing) is a kind of spamdexing (spamming aimed at search engines). The technique involves making repeated web site requests using a fake referer URL to the site the spammer wishes to advertise. Sites that publish their access logs, including referer statistics, will then inadvertently link back to the spammer's site. These links will be indexed by search engines as they crawl the access logs.
This benefits the spammer because the free link improves the spammer site's search engine ranking owing to link-counting algorithms that search engines use.
As with e-mail 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 value to the links.
- "Referrer Bombing has caused some of my sites to instantly disappear from google SERP". 22 September 2009. Retrieved 2013-11-19.
- Abbatiello, James (27 December 2011). "RefControl". Retrieved 2013-11-19.
- A proposal on addressing referrer spam - technical overview and ideas for combatting the practice
- www.codegolem.com Technical article about implementing an Anti-Referrer-Spam Module in ASP.NET/C#
- Using .htaccess to block referrer spam Technical Article about how to block referrer spam with Htaccess