Spamming blogs can also be known as blog spam, comment spam and splogs. All of these are known as spamdexing. Any website that accepts and displays hyperlinks may well become a target of blog spamming.
The spamming of blogs, forums, chat rooms, etc is when comments are automatically posted that are promoting spammers sites. These comments rarely feature any text and normally just consist of the spammers link.
By doing this spammers are increasing there search engine ranking, which can result in the spammers site being listed ahead of other sites. Spammers use these chat rooms, forums, blogs, etc to post links back to their site because it is a way of getting people to visit their site and, sadly, sometimes spend money on the spammers products.
Blog spamming originates from guestbook spamming. Spammers would visit sites only to fill the sites guestbook up with numerous links taking you to their site. Guestbooks were intended to be used by genuine visitors to the site, for them to comment on the use of the site. Spammers rarely even bother to add a comment to the various links they are posting; if they do it would simply say something like cool...