Getting nofollow linkbacks from wordpress blog provide any value in google SE. It increase ranking of our blog?
No you won't get any link juice from a nofollow link but it'll be indexed and will provide traffic benefits to your blog.
there is no value in nofollow links, nofollow links are ignored nor they get value from page, nor indexed.
No use of posting unnecessary links on the no-follow comments. If you do, you could be penalised by Google. I even delete the comments which have other site/blogs links in it.
It really depends upon the value of each of those backlinks. Backlinks have two effects a) they remind google that you website or blog is active and this is reflected in an increase in your SERPS ranking (providing that you don't build too many too quickly. b) Backlinks also increase your page rank, which is a measure of the importance of your site. If your backlinks are from sites with a higher PR then yours then this in thoery should boost your own PR over time.
Nofollow llinks might get you some traffic, and they are also indexed, but they won't give you any PR juice. But they definetely don't hurt your serp either. I would say, don't focus on building nofollow, but if you get some (ex. you want to comment realy good post) that's ok.
No follow backlinks wont hurt you. But it wont help your rank. But most of the time no follow blogs have a good traffic.
Any "nofollow" link won't help you rank better in the serps. Same goes to any link coming from any social media site that contains "nofollow" links. Otherwise, many spam sites would start ranking first due to their incredible effort when spamming blogs with comments.