Blog spam is a type of spam where the target of spamming are weblogs.
In 2003, this type of spam took advantage of the open nature of comments in the blogging software Movable Type by repeatedly placing comments to various blog posts that provided nothing more than a link to the spammer's commercial web site.
What is the point of this "link spam"? In theory, adding links that point to the spammer's web site would increase the page rankings for the site in the search engine Google. An increased page rank means the spammer's commercial site would be listed ahead of other sites for certain Google searches, increasing the number of potential visitors and paying customers.
Jay Allen created a free plugin, called MT-BlackList, for Movable Type that attempts to alleviate this problem.
A similar type of spamming had been previously observed in internet guestbooks, where spammers would repeatedly fill a guestbook with nothing but links to their own site to increase search engine rankings.
Link spam is also spreading to wikis around the World Wide Web including this one (see Wikipedia:Spam). Link spam typically appears on a wiki's sandbox page. This blacklist page documents some of this activity by listing offending URLs and IP_addresses.
