The reasons that I've done it before are:
- I don't know what spam comment is.
- I have no idea it is consider a spam.
- I want to build an external links.
As defined by wikipedia: Spam in blogs is a form of spamdexing. It is done by automatically posting random comments or promoting commercial services to blogs or other publicly accessible online discussion boards. 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.
Hard fact about Spam Comment
Source: Google Webmaster Central Blog
FACT: Abusing comment fields of innocent sites is a bad and risky way of getting links to your site. If you choose to do so, you are tarnishing other people's hard work and lowering the quality of the web, transforming a potentially good resource of additional information into a list of nonsense keywords.
FACT: Comment spammers are often trying to improve their site's organic search ranking by creating dubious inbound links to their site. Google has an understanding of the link graph of the web, and has algorithmic ways of discovering those alterations and tackling them. At best, a link spammer might spend hours doing spammy linkdrops which would count for little or nothing because Google is pretty good at devaluing these types of links. Think of all the more productive things one could do with that time and energy that would provide much more value for one's site in the long run.
FACT: Having original and useful content and making your site search engine friendly is the best strategy for better ranking. With an appealing site, you'll be recognized by the web community as a reliable source and links to your site will build naturally.
What are Google thoughts on blog commenting? Obviously spammers out there are using this technique to build links. What is google doing to combat this?
What can I do to avoid spam on my blog?
Source: Google Webmaster Central Blog
Comments can be a really good source of information and an efficient way of engaging a site's users in discussions. This valuable content should not be replaced by gibberish nonsense keywords and links. For this reason there are many ways of securing your application and disincentivizing spammers.
- Disallow anonymous posting.
- Use CAPTCHAs and other methods to prevent automated comment spamming.
- Turn on comment moderation.
- Use the "nofollow" attribute for links in the comment field.
- Disallow hyperlinks in comments. *For now this is not possible for blogger a.k.a. blogspot
- Block comment pages using robots.txt or meta tags. *For now this is not possible for blogger a.k.a. blogspot
For numbers 1,2,3 you can do this by logging in to your account then click -> Settings -> Comments -> change Who Can Comment?, Comment moderation to your desired choices and Show word verification for comments? to yes. For number 4 you can do this by adding rel='nofollow' attribute to your anchor tags "<a>" Example: <a href="http://www-reviews.blogspot.com" rel="nofollow">WWW-Reviews</a> Another important thing is to add rel="nofollow" to your comment author link
To do this first log in to your account -> Layout -> Edit HTML -> Check Expand Widget Templates -> Under the Edit Template Box, Search for <a expr:name='data:comment.anchorName'/> and add rel='nofollow'. The code should look like this <a expr:name='data:comment.anchorName' rel='nofollow'/> Then click Save Template and your all good.
Does your blog already have spam comments?
I suggest that you start deleting those comments as early as possible. Invest time to get rid of unwanted comments before it hunts you back.
If you have any questions or suggestions, don't hesitate to comment it.