Why spam commenting will not work for you
Leaving spam comments to promote your blog may seem tempting enough but it's best to avoid it. That is, if you want to be taken seriously and see your blog last long enough for your grandchildren to appreciate. Here are reasons why leaving spam comments to promote your blog are NOT the way to go:
You're being watched
These days, you spam someone once and you'll be branded for life. Or at least the blog or business you're trying to promote will be. The CAN-SPAM Act of 2003 makes sure spam is controlled and no one can wave it around like a weapon.
Becoming associated with spam is bad news for your blog. People hate spam… period. They will be more than happy to report you to your host provider or even your affiliate companies and avoid your blog altogether. And yes, Akismet and a host of other plug-ins designed to fight spam will be watching.
You will be penalized
By leaving spam comments on another website with the sole purpose of promoting your blog, you give that website's owner the permission to become a witness against you. Your host provider will cut off ties with you and if you're using your blog to promote an affiliate's products, even your affiliate will drop you.
Should this happen, you will have to start all over again, from square one, with a tarnished reputation. If you leave more spam comments in the future, you'll only be repeating the cycle all over again, all to your detriment.
You'll be seen as unprofessional
Leaving spam comments to promote a blog is for the lazy, the uninformed and the desperate. Why else would you use a technique that is generally viewed as unsavory? If you're unprofessional, your visitors will find it difficult to trust you ever again.
You'll be violating certain unwritten codes
The reason why comments are allowed in websites is to provide people a platform with which to interact. Blogs, forums and discussion boards are large meeting places, open to people regardless of their age, sex, location or personal beliefs, with the implicit agreement that those who participate will be respected for their beliefs.
By leaving spam comments on these sites mainly to promote your blog, you break this code of trust.
Leaving spam comments can increase your blog's ranking... artificially
Although an artificial increase in ranking can mean good news for your blog (it will allow your site to appear high in search engine rankings), this is only an initial effect, sort of like anesthesia. Soon, it will wear off.
This is particularly true if your blog has nothing else to offer. Visitors who have been driven to your blog through search engine links (which you were able to achieve artificially) will sniff around your site and if they find nothing there, they'll leave soon enough, never to come back.
Worse, word might even get around that your website is filled with nothing but air. If you must promote your blog this way, make sure you have the content to make visitors stay.