What is Do follow?
The excerpt below was copied from here
“Backlinks are very important for your websites. They are like votes cast by one respectable website to another, and they will greatly increase the site’s traffic. When one gets many backlinks, one’s site’s ranking in search engine results will skyrocket. Search engines use programs called search bots or web crawlers to access and index web pages. That’s how you see websites in the search results of Google and Yahoo!.
If your site ranks high for any search terms related to the products you promote, you can get several potential customers (a very daunting task indeed). Now, in order for you to get business, you must rank high in search engines, and the most important thing that will help you in this is link building.
You should try to get links from whichever sources available. It is a tactic in Search Engine Optimization (SEO). In the past, when you commented in a blog, you could get a backlink, just by using this HTML code:
When you placed this piece of code within your comment, you used to get backlink from it. It was highly beneficial for you to rank high (especially if the blog is high PageRank).
How to Make Your Blogger Blog DoFollow?
Before doing these steps, you should allow anonymous comments by going to Settings in Blogger and then Comments. You may enable or disable the moderation. You will soon know the importance of moderation, however. Here are the steps to make comments DoFollow:
1. Go to Blogger layout (in new Blogger) and click Edit HTML.
2. Check Expand Widget Templates.
3. Search for ‘NoFollow.’ You will find at least two of them in the code.
4. Remove “rel=”nofollow”” from the tag that starts with “<a expr:href=’data:comment.authorUrl’”
5. The second nofollow attribute is for pingback/trackback URLs (blogs that link to your post and ping it). You may or may not retain these URLs. It’s completely optional.
6. That’s it! Enjoy. Your comment’s title is now ‘DoFollow.’
In old Blogger, you can do this by editing HTML in Template tab.
By doing this in Blogger, the comment title will be made DoFollow. But the backlinks will be available only if you comment with Name and URL field enabled. The comment body links will still remain NoFollow. So, you needn’t place any link in the body, just place the required anchor text in the name field, and URL in the URL filed and comment; it will become a DoFollow backlink to your URL.”