Blog spamming or comment spam is one of the many issues pertaining to the use of SEO or search engine optimization. It is a form of spamdexing which involves posting random comments or promoting commercial services to blogs and other forms of publicly accessible online discussion boards such as wikis and guestbooks which can be done automatically and manually.
Because of the severity of blog spamming in manipulating SERPs (search engine result pages), as well as causing floods in blogs and other forms of publicly accessible online discussion boards, several possible solutions have been made by both search engines and individuals to prevent or avoid the use comment spams in their blogs. One of the most popular is the nofollow tag.
NoFollow Tag
The rel"nofollow" attribute was started by Google which is aimed to minimize the use of manual comment spams in blogs and other publicly accessible online discussion boards. According to Google, hyperlinks with the nofollow tag would not be crawled or influence the link target's ranking in the search engine's index. The Yahoo and MSN search engines have also come to respect this tag.
According to many SEO Philippines consultants, using the nofollow tag is much more easier than other solutions to avoiding comment spam. Because of its popularity, most weblogs now marks reader-submitted links this way by default. However, there are several flaws to the use of the nofollow tag solution.
According to many professionals, link spammers would still ontinue to spam everyone to reach the sites that do not use rel"nofollow". They would still also continue to place links for clicking (by surfers) even if those links are ignored by search engines. Another major disadvantage of the nofollow tag is that it may reduce the value of legitimate comments.
According to many SEO Philippines consultants, using the nofollow tag doesn't really prevent comment spams, it is only Google's effort to reduce the effect of heavy inter-blog linking on page ranking as well as to minimize its own filtering efforts. Automatic comment spamming softwares would still spam comments on blogs with the nofollow tag.
Advancements
There are several advancements to the use of the rel"nofollow" tag. Some servers, particularly the sophisticated ones, could spare the nofollow for links submitted by trusted users like those registered for a long time, on a whitelist, or with a high karma. Websites that use such techniques includes Slashdot.
Slashdot use improvised nofollow implementations like adding rel"nofollow" only for potentially misbehaving users. According to many SEO Philippines consultants, Slashdot also uses the poster's karma as a determinant in attaching a nofollow tag to user submitted links.
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