Spam in blogs

(Spam Twitter)-Spam in blogs (also called simply blog spam or comment spam is a form of spamdexing. (Note that blogspam has another, more common meaning, namely the post of a blogger who creates no-value-added posts to submit them to other sites.) It is done by automatically posting random comments or promoting commercial services to blogs, wikis, guestbooks, or other publicly accessible online discussion boards. Any web application that accepts and displays hyperlinks submitted by visitors may be a target.

Adding links that point to the spammer's web site artificially increases the site's search engine ranking. An increased ranking often results in the spammer's commercial site being listed ahead of other sites for certain searches, increasing the number of potential visitors and paying customers.

History

This type of spam originally appeared in internet guestbooks, where spammers repeatedly fill a guestbook with links to their own site and no relevant comment, to increase search engine rankings. If an actual comment is given it is often just "cool page", "nice website", or keywords of the spammed link.

In 2003, spammers began to take advantage of the open nature of comments in the blogging software like Movable Type by repeatedly placing comments to various blog posts that provided nothing more than a link to the spammer's commercial web site. Jay Allen created a free plugin, called MT-BlackList.

Possible solutions

Disallowing multiple consecutive submissions

It is rare on a site that a user would reply to their own comment, yet spammers typically will do. Checking that the user's IP address is not replying to a user of the same IP address will significantly reduce flooding. This, however, proves problematic when multiple users, behind the same proxy, wish to comment on the same entry.

Blocking by keyword

Blocking specific words from posts is one of the simplest and most effective ways to reduce spam. Much spam can be blocked simply by banning names of popular pharmaceuticals and casino games.

This is a good long-term solution, because it's not beneficial for spammers to change keywords to "vi@gra" or such, because keywords must be readable and indexed by search engine bots to be effective.