The backlinks in dofollow are the links that present no indication to the search engine robots to prevent them from following these links. These links are counted as a vote for the web page that receives them.
The SEO supporters of dofollow backlinks believe, correctly, that in terms of SEO, only these links transmit juice (link juice) and thus allow Google or Bing to use it as a signal.
On the contrary, any nofollow link provides a clear and precise instruction to robots, with the rel = nofollow attribute, to ignore them. A technique that allows webmasters to quote a web page without losing all the juice (PR) of their own page. Because, an outgoing link is a little pagerank of the page that goes to the page cited.
As mentioned above, backlinks in nofollow do not transmit juice, as robots are expressly asked not to take them into account.
But, some SEO experts believe that nofollow links are also important because they provide another form of profit. To know that these backlinks bring as much traffic, sometimes more, than dofollow backlinks from referring sites.
Thus, the importance of their click-through rate would also remain a signal which search engines would take into account and eventually count them. The more clicks on a link in nofollow, the more the landing page would gain notoriety and importance.
An excellent example of this argument on nofollow backlinks is the links inserted into the blog comments. Almost all blogs automatically include the rel = nofollow attribute for all commentator links to discourage spamming. Nevertheless, a good well-argued comment on a popular blog can give you very many visits in a period of time.
Another example: we know that backlinks on Wikipedia are now in nofollow because of many webspams from some volunteer contributors. Still, being quoted on Wikipedia provides a lot of regular traffic. And also helps with web positioning because of its web authority status.
What do you think about backlinks?
When it comes to SEO, I have always considered that SEO is not an exact science. And what works for a referrer may not necessarily work for another referrer.
For the backlinks you receive, they must present a natural side. This is why it would be reasonable to voluntarily mix the 2 types of links, namely find backlinks in dofollow but also backlinks in nofollow.
Having only dofollow backlinks can seem suspicious to the “eyes” of search engines. Nofollow links should be part of your netlinking strategy.