Nofollow is an HTML attribute given as instruction to search engine crawlers ,not to crawl the hyperlinks specified by the nofollow tags. So if are inserting a nofollow tag after a hyperlink , then the target will not carry any value for that link in search engine positions . They are widely used by blogs and forums to avoid spam comments and posts for getting backlinks.
Similarly in Blogger , the comment section is nofollow by default .You can add or remove nofollow from blogger comments by changing its value in blogger template . Removing nofollow will invite more people to comment on your blog and also more fame in webmaster forums.
Well , this can be in few steps
Go to edit HTML ,click on Expand Widget Template , Press Ctrl+F and search for nofollow ..
Find code secrion ,
<a expr:href=’data:comment.authorUrl’ rel=’nofollow’>
So by this line , the author URL in comment section is made nofollow . Change the nofollow attribute to follow and save the template .
Add nofollow in blogger post section
<a href=”http://www.yahoo.com/yahoomsg8.exe ” rel=nofollow”>Download</a>
This is an example download link for yahoo messenger in Compose and edit HTML view in blogger. Here i have added a nofollow tag just after the quotes closing the download link. It should be done always if you have download link which is not hosted on your on server ( well I am not dragging the topic by explaining the theory behind it ).
PN: You can check nofollow/dofollow by using a Firefox addon called nodofollow.