During the early days of blogging when you comment on blogs the back link to your website improved your search engine rankings. For example, if you comment on a blog with a higher Page Rank, Google would pass some credit to your website. Many web users who saw commenting as a viable option to increase their search engine ranking, started to abuse the system. This led to the creation of the nofollow attribute.
The nofollow attribute basically tells a search engine to not to give any credit to the hypertext link. Search engines may follow the link to discover your website, but, they will not pass any credit to your website.
But there is a community of users who still believe passing on some link love to fellow bloggers and commentators is the right thing to do. Blogs that pass on some link love are informally called as dofollow blogs.
You can try to improve your search engine ranking by commenting on these blogs. Please note that I am not proposing this practice as a SEO strategy to build back links to your website. What I am saying is to be smart when you comment. For example, there are two blogs in the same topic. Blog A is a nofollow blog and Blog B is a dofollow blog. I would be inclined to comment on Blog B rather than Blog A.
So how do you find dofollow blogs?
1. Use SEO for Firefox Plug-in
SEO for Firefox is a handy plug-in that will work with your Firefox browser. Once the plug-in is installed when you view a web page, all nofollow links will appear with a red background. Please refer to the screen shot below. It shows the comments section in my blog. Note that all the comment links show up with a red background. This is because my comment links are nofollow links.
2. Look for websites that contain “U Comment, I Follow” images.
A number of dofollow blogs use the above image. Many dofollow blogs use the same standard ALT text of “U Comment, I Follow”. So the trick is to search for this ALT text in Google image search. Please note that you have to use double quotes to get better results. Using this technique you will come across a lot of dofollow blogs.
3. Look at dofollow directories
There are dofollow blog directories on the Internet. You can use such directories to find dofollow blogs by subject area. DofollowBlogs is one example of such a directory. Please note that these directories may not be up-to-date. For example, if the blog owner recently changed his blog from dofollow to nofollow you might be misled.
Finally, I would like to reiterate the point I made earlier. Do not comment on dofollow blogs purely to gain some SEO benefits. Only comment on blogs that you are genuinely interested in. During my search for dofollow blogs I came a across a very good blog on graphic and logo design. The name of the blog is LimeShot. Now I am a reader of this blog and I am genuinely interested in the contents. Whenever I comment on this blog, I get some link love too!