Many people have a doubt regarding this question about a do-follow and no-follow blog. Well in my past research i looked into this matter and got some interesting information about them.
Generally a new blogger will make as many blogs as possible as it genuinely helps in SERPs and attracts a reasonable amount of traffic towards the website or blog. But not each and every blogs are crawled by search engines.
There are 2 types of blogs. One having a “Do-Follow” in their tags and the other obviously as i have explained earlier a “No-Follow” in their pages.
The “Do-Follow” blogs generally are blogs that are crawled by search engines like Google, Yahoo, etc. The below theory will help you to understand it better.
In the early days of blogging, many unwanted spammers were abusing the commenting pages of these blogs with their yuck links, and indirectly trying to promote their sites. To combat such an issue, Google started implementing the “No-Follow” tags in its index. Furthermore, this “No-Follow” tag was soon grasped by WordPress.com (one of the most user-friendly free blogging website). The people at wordpress starting implementing the same strategy while running their scripts in their commenting page. Basically what it means is that the URL’s posted in the commenting pages are not considered by search engines like Google.com and also these urls are not approved by google in their page rank theory. The thinking behind this was this step would resist spammers from posting yucky commenting URLs on blogs.
Was it worth It ?? Well, as per the spamming (which was over 7000) on one of my blog is concerned, it reflects that this did not seem to work as my blog commenting page are “No-Followed”.
What was worth it is this Askimet SPAM plug-in in wordpress.
But unfortunately, the “no follow” tag did have one unforeen result. Genuine commentors that had placed legitimate comments on various blogs were also not permited from doing this because they were not receiving any “link juice” from their commenting, either.
There is known to be a movement from various blogging websites and also search engines to allow the “Do-Follow” tags only and restraining the “No-Follow” tags to encourage people to post comments on the blogs. In wordpress, there is a option to turn off the “No-Follow” tag by a given plugin.
By advertising and promoting your blog as a “Do-Follow” tagged blog, you will surely grab the attention of others posters to leave their comments on your blog.
So according to me, its well advised to promote your blog site on “Do-Follow” tagged blogs as it generally extracts more traffic and encourages others to leave comments on them.