Do-follow link is nothing but the link juice performed in the SEO. Link juice is the technique using which you used to pass the link from one website to another. Using it, you come to know that how powerful the linking between the one site to another or in-between is. The hyperlinks are used for it.
The important factor while ranking your website by the search engine is that how many quality links you have added. It is not like that if there are more number of links then search engine will rank your website on top, it depends on which type of links you have added.
The more authority a page has, the more link juice it will pass.
No-Follow link -
It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing from occurring in the first place.
Recently Google has said that they will still count the nofollow link as an outgoing link in terms of the distribution of page rank from your page. Though again it also depends on where that nofollow link is placed. Placing a nofollow link at the bottom of the page has the least impact, and when placed at the top of the page, it carries some impact.
The necessity of the nofollow tag highlights the crooked and spammy mentality commonly associated with SEO.
Hope this will clear your all doubts.
