In blogs I got the nofollow links on comment like http://www.example.com/xyz?url=http://www.minervait.com in few I got direct link http://www.minervait.com is the first link worth full ?? did search engine likes it ?
Hey, In SEO, No strategy is worth full, No follow blog commenting will help at the view point of your link popularity.
Nofollow backlinks are useful but only if you are having them from the site which is having heavy traffic or else they are worthless.