Do-follow- In simple language Google follows do-follow links and gives backlinks to your site and link juice. Do-follow links effect on your ranking.

No-follow- Simply Google does not follow no-follow links and does not give you link juice.

So, main question is: “why we are collecting no-follow links”?

To my point of view – Do-follow links increase our site’s ranking and traffic but no-follow links increase traffic only. The no-follow links don’t affect ranking but so many SEO specialists say that indirectly no-follow links also affect ranking.
So, try to collect do-follow links the more but we can’t avoid no-follow links.
If anyone knows about this matter then please post here. We have been searching exact point to this question for long time. So, please put your little efforts to solve this problem with leading SEO company India.