Can Disqus and CommentLuv help

Dear members,
I have heard that commenting on blogs which are empowered with Disqus and CommentLuv system may give link juice. Is it true?
Is there a link juice if I make a commentluv or Disqus profile and comment on sites with useful and relevant stuff?
I am new to seo, can you please help me out in this.
Till now, I make sure that the comments are relevant and add value to the blog. however i only get nofollow backlinks which I think have zero value.
Can you please tell me commenting through Disqus & commentLuv help in link building.
Regards,
Shekhar

Comments do several things:

• Comments make people stay on page longer.
• Comments grow your content by crowd sourcing part of it.
• Comments increase your match count.
• Comments give people a reason to check back to the same page multiple times.
• Comments make you content more interesting thus bring people back to your website more regularly.

An active comment thread might get shared more often... so it is plausible that it might help with link building.

No they don't pass linkjuice, but on a high profile post, they can send good traffic.

I like the cleanliness of Disqus, but no seo love there...

hahaha.. I got my answer for disqus.
However, dear members, I am skeptical about commentluv.
I have heard that commentluv helps in link building as it helps in promoting a balanced nofollow and ******** link with all comment.
Oh, it's really complicated because I have seen a few big blogs starting from there.